Created attachment 164837 [details]
The system settings ap.

SUMMARY
***
After updating from plasma 5.27.* to 5.90.0 (plasma 6 beta 1) the system settings app has an error loading QML files leaving the app unusable.

***


STEPS TO REPRODUCE
Getting on plasma 6 (when the original issue with system settings started happening) :
I originally was on some stable version of plasma and decided to try out plasma 6 beta 1 and since I am on arch linux these were my steps to reproduce what I did.
Plasma 6 beta 1: 
1. Open a terminal application to run a command.
2. Run the command  with a text editor of choice (nano, vim, etc)   sudo nano /etc/pacman.conf
3. Enter the password if requested.
4. Scroll all the way down to the repository section
5. If not already added, add the kde-unstable repo to the TOP of the other repos and enable extra-testing by removing the # in front of those lines. 
example: 

[kde-unstable]
Include = /etc/pacman.d/mirrorlist

#[core-testing]
#Include = /etc/pacman.d/mirrorlist

[core]
Include = /etc/pacman.d/mirrorlist

[extra-testing]
Include = /etc/pacman.d/mirrorlist

[extra]
Include = /etc/pacman.d/mirrorlist

6. Save the file and exit the file editor of choice to return to the terminal.

7. Run a pacman package update.  You can use any AUR helper ( yay, paru, etc)      paru -Syyu
this went and installed all those packages that I needed to update to plasma 6 beta 1 from my current version I was at at the time which I don't remember. Probably some time around 5.27.* As I usually update packages once a week.

8. reboot (logout could work as well) and log back into plasma at the sddm and you should see the welcome center saying the version of plasma 6 you are on. In my case at the time it was plasma 6 beta 1. but the main issue continues to happen in the RC1 

Settings app:
1. Click on settings app (skip to step #4 ) or Open a terminal application to run a command.
2. Run the command    systemsettings   to launch the system settings app for KDE plasma.
3. You should see the app launch, go back to the terminal and check for the errors that I have posted below.
4. Now on the system settings app that launched go to About this System or any tab that primarily uses a QML file to function. And notice the blank page with the errors posted below. 
OBSERVED RESULT 
When running the app from the terminal:
 HackTop :: ~ »  systemsettings            
Using fontconfig file: "/home/ash/.fonts.conf"
KPackageStructure of KPluginMetaData(pluginId:"org.kde.plasma.worldmap", fileName: "/usr/share/plasma/wallpapers/org.kde.plasma.worldmap/metadata.json") does not match requested format "Plasma/Wallpaper"
KQuickPadding is both anonymous and named
qt.qml.typeresolution.cycle: Cyclic dependency detected between "qrc:/qt/qml/org/kde/desktop/private/GlobalSonnetSettings.qml" and "qrc:/qt/qml/org/kde/desktop/private/MobileTextActionsToolBar.qml"
qt.qml.typeresolution.cycle: Cyclic dependency detected between "qrc:/qt/qml/org/kde/desktop/private/GlobalSonnetSettings.qml" and "qrc:/qt/qml/org/kde/desktop/private/TextFieldContextMenu.qml"
qt.qml.typeresolution.cycle: Cyclic dependency detected between "qrc:/qt/qml/org/kde/desktop/private/MobileTextActionsToolBar.qml" and "qrc:/qt/qml/org/kde/desktop/private/TextFieldContextMenu.qml"
qt.qml.typeresolution.cycle: Cyclic dependency detected between "qrc:/qt/qml/org/kde/desktop/private/GlobalSonnetSettings.qml" and "qrc:/qt/qml/org/kde/desktop/MenuItem.qml"
qt.qml.typeresolution.cycle: Cyclic dependency detected between "qrc:/qt/qml/org/kde/desktop/private/MobileTextActionsToolBar.qml" and "qrc:/qt/qml/org/kde/desktop/MenuItem.qml"
qt.qml.typeresolution.cycle: Cyclic dependency detected between "qrc:/qt/qml/org/kde/desktop/private/TextFieldContextMenu.qml" and "qrc:/qt/qml/org/kde/desktop/MenuItem.qml"
qt.qml.typeresolution.cycle: Cyclic dependency detected between "qrc:/qt/qml/org/kde/desktop/private/GlobalSonnetSettings.qml" and "qrc:/qt/qml/org/kde/desktop/private/CheckIndicator.qml"
qt.qml.typeresolution.cycle: Cyclic dependency detected between "qrc:/qt/qml/org/kde/desktop/private/MobileTextActionsToolBar.qml" and "qrc:/qt/qml/org/kde/desktop/private/CheckIndicator.qml"
qt.qml.typeresolution.cycle: Cyclic dependency detected between "qrc:/qt/qml/org/kde/desktop/private/TextFieldContextMenu.qml" and "qrc:/qt/qml/org/kde/desktop/private/CheckIndicator.qml"
qt.qml.typeresolution.cycle: Cyclic dependency detected between "qrc:/qt/qml/org/kde/desktop/private/GlobalSonnetSettings.qml" and "qrc:/qt/qml/org/kde/desktop/private/MobileTextActionsToolBar.qml"
qt.qml.typeresolution.cycle: Cyclic dependency detected between "qrc:/qt/qml/org/kde/desktop/private/GlobalSonnetSettings.qml" and "qrc:/qt/qml/org/kde/desktop/private/TextFieldContextMenu.qml"
qt.qml.typeresolution.cycle: Cyclic dependency detected between "qrc:/qt/qml/org/kde/desktop/private/MobileTextActionsToolBar.qml" and "qrc:/qt/qml/org/kde/desktop/private/TextFieldContextMenu.qml"
qt.qml.typeresolution.cycle: Cyclic dependency detected between "qrc:/qt/qml/org/kde/desktop/private/GlobalSonnetSettings.qml" and "qrc:/qt/qml/org/kde/desktop/MenuItem.qml"
qt.qml.typeresolution.cycle: Cyclic dependency detected between "qrc:/qt/qml/org/kde/desktop/private/MobileTextActionsToolBar.qml" and "qrc:/qt/qml/org/kde/desktop/MenuItem.qml"
qt.qml.typeresolution.cycle: Cyclic dependency detected between "qrc:/qt/qml/org/kde/desktop/private/TextFieldContextMenu.qml" and "qrc:/qt/qml/org/kde/desktop/MenuItem.qml"
qt.qml.typeresolution.cycle: Cyclic dependency detected between "qrc:/qt/qml/org/kde/desktop/private/GlobalSonnetSettings.qml" and "qrc:/qt/qml/org/kde/desktop/private/CheckIndicator.qml"
qt.qml.typeresolution.cycle: Cyclic dependency detected between "qrc:/qt/qml/org/kde/desktop/private/MobileTextActionsToolBar.qml" and "qrc:/qt/qml/org/kde/desktop/private/CheckIndicator.qml"
qt.qml.typeresolution.cycle: Cyclic dependency detected between "qrc:/qt/qml/org/kde/desktop/private/TextFieldContextMenu.qml" and "qrc:/qt/qml/org/kde/desktop/private/CheckIndicator.qml"
kf.kcmutils: Error loading QML file qrc:/kcm/kcm_landingpage/main.qml
kf.kcmutils:     qrc:/kcm/kcm_landingpage/main.qml:18:1: Type KCM.SimpleKCM unavailable
    KCM.SimpleKCM {
    ^
kf.kcmutils:     qrc:/qt/qml/org/kde/kcmutils/SimpleKCM.qml:33:1: Type Kirigami.ScrollablePage unavailable
    Kirigami.ScrollablePage {
    ^
kf.kcmutils:     file:///usr/lib/qt6/qml/org/kde/kirigami/ScrollablePage.qml:67:1: Type Kirigami.Page unavailable
    Kirigami.Page {
    ^
kf.kcmutils:     file:///usr/lib/qt6/qml/org/kde/kirigami/Page.qml:237:13: Type Kirigami.PageRow unavailable
                property Kirigami.PageRow row
                ^
kf.kcmutils:     file:///usr/lib/qt6/qml/org/kde/kirigami/PageRow.qml:180:5: Type OverlayDrawer unavailable
        property OverlayDrawer leftSidebar
        ^
kf.kcmutils:     file:///usr/lib/qt6/qml/org/kde/kirigami/OverlayDrawer.qml:22:1: Type KT.OverlayDrawer unavailable
    KT.OverlayDrawer {
    ^
kf.kcmutils:     file:///usr/lib/qt6/qml/org/kde/kirigami/templates/OverlayDrawer.qml:120:56: Cannot assign object of type "KTP.IconPropertiesGroup" to property of type "IconPropertiesGroup_QMLTYPE_70*" as the former is neither the same as the latter nor a sub-class of it.
        property KTP.IconPropertiesGroup handleClosedIcon: KTP.IconPropertiesGroup {
                                                           ^
qt.qml.typeresolution.cycle: Cyclic dependency detected between "qrc:/qt/qml/org/kde/desktop/private/GlobalSonnetSettings.qml" and "qrc:/qt/qml/org/kde/desktop/private/MobileTextActionsToolBar.qml"
qt.qml.typeresolution.cycle: Cyclic dependency detected between "qrc:/qt/qml/org/kde/desktop/private/GlobalSonnetSettings.qml" and "qrc:/qt/qml/org/kde/desktop/private/TextFieldContextMenu.qml"
qt.qml.typeresolution.cycle: Cyclic dependency detected between "qrc:/qt/qml/org/kde/desktop/private/MobileTextActionsToolBar.qml" and "qrc:/qt/qml/org/kde/desktop/private/TextFieldContextMenu.qml"
qt.qml.typeresolution.cycle: Cyclic dependency detected between "qrc:/qt/qml/org/kde/desktop/private/GlobalSonnetSettings.qml" and "qrc:/qt/qml/org/kde/desktop/MenuItem.qml"
qt.qml.typeresolution.cycle: Cyclic dependency detected between "qrc:/qt/qml/org/kde/desktop/private/MobileTextActionsToolBar.qml" and "qrc:/qt/qml/org/kde/desktop/MenuItem.qml"
qt.qml.typeresolution.cycle: Cyclic dependency detected between "qrc:/qt/qml/org/kde/desktop/private/TextFieldContextMenu.qml" and "qrc:/qt/qml/org/kde/desktop/MenuItem.qml"
qt.qml.typeresolution.cycle: Cyclic dependency detected between "qrc:/qt/qml/org/kde/desktop/private/GlobalSonnetSettings.qml" and "qrc:/qt/qml/org/kde/desktop/private/CheckIndicator.qml"
qt.qml.typeresolution.cycle: Cyclic dependency detected between "qrc:/qt/qml/org/kde/desktop/private/MobileTextActionsToolBar.qml" and "qrc:/qt/qml/org/kde/desktop/private/CheckIndicator.qml"
qt.qml.typeresolution.cycle: Cyclic dependency detected between "qrc:/qt/qml/org/kde/desktop/private/TextFieldContextMenu.qml" and "qrc:/qt/qml/org/kde/desktop/private/CheckIndicator.qml"
kf.kcmutils: Error loading QML file qrc:/kcm/kcm_about-distro/main.qml
kf.kcmutils:     qrc:/kcm/kcm_about-distro/main.qml:15:1: Type KCM.SimpleKCM unavailable
    KCM.SimpleKCM {
    ^
kf.kcmutils:     qrc:/qt/qml/org/kde/kcmutils/SimpleKCM.qml:33:1: Type Kirigami.ScrollablePage unavailable
    Kirigami.ScrollablePage {
    ^
kf.kcmutils:     file:///usr/lib/qt6/qml/org/kde/kirigami/ScrollablePage.qml:67:1: Type Kirigami.Page unavailable
    Kirigami.Page {
    ^
kf.kcmutils:     file:///usr/lib/qt6/qml/org/kde/kirigami/Page.qml:237:13: Type Kirigami.PageRow unavailable
                property Kirigami.PageRow row
                ^
kf.kcmutils:     file:///usr/lib/qt6/qml/org/kde/kirigami/PageRow.qml:180:5: Type OverlayDrawer unavailable
        property OverlayDrawer leftSidebar
        ^
kf.kcmutils:     file:///usr/lib/qt6/qml/org/kde/kirigami/OverlayDrawer.qml:22:1: Type KT.OverlayDrawer unavailable
    KT.OverlayDrawer {
    ^
kf.kcmutils:     file:///usr/lib/qt6/qml/org/kde/kirigami/templates/OverlayDrawer.qml:120:56: Cannot assign object of type "KTP.IconPropertiesGroup" to property of type "IconPropertiesGroup_QMLTYPE_70*" as the former is neither the same as the latter nor a sub-class of it.
        property KTP.IconPropertiesGroup handleClosedIcon: KTP.IconPropertiesGroup {
                                                           ^


END OF TERMINAL APP ERRORS 



When inside the 'About this System' tab in the system settings app:

About this System

Error loading QML file.

qrc:/kcm/kcm_about-distro/main.qml:15 Type KCM.SimpleKCM unavailable
qrc:/qt/qml/org/kde/kcmutils/SimpleKCM.qml:33 Type Kirigami.ScrollablePage unavailable
file:///usr/lib/qt6/qml/org/kde/kirigami/ScrollablePage.qml:67 Type Kirigami.Page unavailable
file:///usr/lib/qt6/qml/org/kde/kirigami/Page.qml:237 Type Kirigami.PageRow unavailable
file:///usr/lib/qt6/qml/org/kde/kirigami/PageRow.qml:180 Type OverlayDrawer unavailable
file:///usr/lib/qt6/qml/org/kde/kirigami/OverlayDrawer.qml:22 Type KT.OverlayDrawer unavailable
file:///usr/lib/qt6/qml/org/kde/kirigami/templates/OverlayDrawer.qml:120 Cannot assign object of type "KTP.IconPropertiesGroup" to property of type "IconPropertiesGroup_QMLTYPE_60*" as the former is neither the same as the latter nor a sub-class of it.

EXPECTED RESULT
Seeing no errors in the terminal app of choice when running **systemsettings**  plus the opening of the systemsettings app in it's normal mannor with nothing saying qml file 

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: 
OS: Arch Linux
(available in About System)
KDE Plasma Version: 5.92.0 (plasma 6.0 RC1)
KDE Frameworks Version: 5.248.0
Qt Version: 	6.7.0 (beta1-2)

ADDITIONAL INFORMATION
this issue has been present on package update and reinstall of the entire plasma de and even up now on plasma RC1
HeLp ME PLZZZ