SUMMARY
***
I raise this bug report here although I am not sure if this is the correct place. In any case, my issue is that I cannot **save** files in my Google Drive. And I am suspecting that this is a portal-related issue because I have the same issue with Chrome and Firefox. However, I have no problems when I use KDE-native applications, for example Okular. 
***


STEPS TO REPRODUCE
1. Open Firefox (of Chrome) provided that you use KDE file dialogs
2. Try to save a file on your google drive

OBSERVED RESULT
No message is displayed, no notification is raised and file is NOT saved in Google Drive. 

EXPECTED RESULT
A notification about the save is raised and file is saved in the Google drive. 

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: openSUSE Tumbleweed/Fedora 36
KDE Plasma Version: 5.27.x (at the time of writing: 5.27.4)
KDE Frameworks Version: 5.105.0

ADDITIONAL INFORMATION
journal logs when I tried to save an STL file on my google drive: 
The issue is happening even when I use private/incognito mode in FF/Chrome, or the FF in troubleshooting mode. 

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Apr 09 20:50:40 desktop.example.com plasmashell[2090]: Could not find the Plasmoid for Plasma::FrameSvgItem(0x55c1bfc13140) QQmlContext(0x55c1bfa33710) QUrl("file:///usr/share/plasma/plasmoids/org.kde.plasma.notifications/contents/ui/global/Globals.qml")
Apr 09 20:50:40 desktop.example.com plasmashell[2090]: Could not find the Plasmoid for Plasma::FrameSvgItem(0x55c1bfc13140) QQmlContext(0x55c1bfa33710) QUrl("file:///usr/share/plasma/plasmoids/org.kde.plasma.notifications/contents/ui/global/Globals.qml")
Apr 09 20:50:40 desktop.example.com plasmashell[2090]: file:///usr/share/plasma/plasmoids/org.kde.plasma.notifications/contents/ui/NotificationPopup.qml:106:15: QML MouseEventListener: Binding loop detected for property "height"
Apr 09 20:50:40 desktop.example.com rtkit-daemon[2038]: Supervising 23 threads of 14 processes of 1 users.
Apr 09 20:50:40 desktop.example.com rtkit-daemon[2038]: Supervising 23 threads of 14 processes of 1 users.
Apr 09 20:50:44 desktop.example.com dbus-daemon[1126]: [system] Activating via systemd: service name='org.freedesktop.hostname1' unit='dbus-org.freedesktop.hostname1.service' requested by ':1.1258' (uid=1000 pid=2535 comm="/usr/lib64/firefox/firefox" label="unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023")
Apr 09 20:50:44 desktop.example.com xdg-desktop-portal-kde[2113]: kf.kio.widgets.kdirmodel: No node found for item that was just removed: QUrl("file:///home/user/downloads/3d print/Battery charger - Skadis.stl")
Apr 09 20:50:44 desktop.example.com systemd[1]: Starting Hostname Service...
░░ Subject: A start job for unit systemd-hostnamed.service has begun execution
░░ Defined-By: systemd
░░ Support: https://lists.freedesktop.org/mailman/listinfo/systemd-devel
░░ 
░░ A start job for unit systemd-hostnamed.service has begun execution.
░░ 
░░ The job identifier is 6957.
Apr 09 20:50:44 desktop.example.com dbus-daemon[1126]: [system] Successfully activated service 'org.freedesktop.hostname1'
Apr 09 20:50:44 desktop.example.com systemd[1]: Started Hostname Service.
░░ Subject: A start job for unit systemd-hostnamed.service has finished successfully
░░ Defined-By: systemd
░░ Support: https://lists.freedesktop.org/mailman/listinfo/systemd-devel
░░ 
░░ A start job for unit systemd-hostnamed.service has finished successfully.
░░ 
░░ The job identifier is 6957.
Apr 09 20:50:45 desktop.example.com kwin_x11[1989]: kwin_core: XCB error: 152 (BadDamage), sequence: 54768, resource id: 12275879, major code: 143 (DAMAGE), minor code: 3 (Subtract)
Apr 09 20:50:47 desktop.example.com dbus-daemon[1839]: [session uid=1000 pid=1839] Activating service name='com.google.code.AccountsSSO.SingleSignOn' requested by ':1.694' (uid=1000 pid=19144 comm="/usr/libexec/kf5/kioslave5 /usr/lib64/qt5/plugins/" label="unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023")
Apr 09 20:50:47 desktop.example.com dbus-daemon[1839]: [session uid=1000 pid=1839] Successfully activated service 'com.google.code.AccountsSSO.SingleSignOn'
Apr 09 20:50:47 desktop.example.com signond[19156]: Cannot use KWindowSystem without a QGuiApplication
Apr 09 20:50:51 desktop.example.com rtkit-daemon[2038]: Supervising 23 threads of 14 processes of 1 users.
Apr 09 20:50:51 desktop.example.com rtkit-daemon[2038]: Supervising 23 threads of 14 processes of 1 users.
Apr 09 20:51:14 desktop.example.com systemd[1]: systemd-hostnamed.service: Deactivated successfully.
░░ Subject: Unit succeeded
░░ Defined-By: systemd
░░ Support: https://lists.freedesktop.org/mailman/listinfo/systemd-devel
░░ 
░░ The unit systemd-hostnamed.service has successfully entered the 'dead' state.
Apr 09 20:51:21 desktop.example.com kioslave5[19223]: kf5.kio.gdrive: Failed to resolve "/Google - Personal/Εκθεση βιβλιου_Αφίσα.pdf"
Apr 09 20:51:22 desktop.example.com kioslave5[19132]: kf.coreaddons: "Could not load plugin from /usr/lib64/qt5/plugins/gsthumbnail.so: Failed to extract plugin meta data from '/usr/lib64/qt5/plugins/gsthumbnail.so'"
Apr 09 20:51:22 desktop.example.com kioslave5[19223]: kf5.kio.gdrive: Failed to resolve "/Google - Personal/Εκθεση βιβλιου_Αφίσα.pdf"
Apr 09 20:51:22 desktop.example.com dbus-daemon[1839]: [session uid=1000 pid=1839] Activating via systemd: service name='org.kde.KIOFuse' unit='kio-fuse.service' requested by ':1.26' (uid=1000 pid=2113 comm="/usr/libexec/xdg-desktop-portal-kde" label="unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023")
Apr 09 20:51:22 desktop.example.com systemd[1810]: Starting Fuse interface for KIO...
░░ Subject: A start job for unit UNIT has begun execution
░░ Defined-By: systemd
░░ Support: https://lists.freedesktop.org/mailman/listinfo/systemd-devel
░░ 
░░ A start job for unit UNIT has begun execution.
░░ 
░░ The job identifier is 490.
Apr 09 20:51:22 desktop.example.com dbus-daemon[1839]: [session uid=1000 pid=1839] Successfully activated service 'org.kde.KIOFuse'
Apr 09 20:51:22 desktop.example.com xdg-desktop-portal-kde[2113]: FUSE request failed: QDBusError("org.kde.KIOFuse.VFS.Error.SchemeNotSupported", "KIOFuse does not suport mounting of URLs with a scheme of gdrive")
Apr 09 20:51:22 desktop.example.com systemd[1810]: Started Fuse interface for KIO.
░░ Subject: A start job for unit UNIT has finished successfully
░░ Defined-By: systemd
░░ Support: https://lists.freedesktop.org/mailman/listinfo/systemd-devel
░░ 
░░ A start job for unit UNIT has finished successfully.
░░ 
░░ The job identifier is 490.
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