SUMMARY
Autostarts only shows apps which are configured in ~/.config/autostart/ but all autostarts should be shown there (just like the name "Autostarts" suggests). Please also show items in /etc/xdg/autostart/.

Many people are looking for a GUI to easily manage their startup applications (https://unix.stackexchange.com/q/374012/233262). Other operating systems like Windows also have it (https://superuser.com/q/1010345/385861). There are good reasons for why people are looking for this and for why this is useful and needed. As this is named "Autostarts" in KDE, the user expects to find all autostart entries and to be able to easily manage them all from there.

STEPS TO REPRODUCE
1. Install Debian12/KDE
2. Enter autostart in the search or go to System Settings -> Startup and Shutdown to open the GUI
3. Try to manage autostarts such as disabling KDE Connect (https://unix.stackexchange.com/q/384306/233262) and Kaccessible that get reenabled to autostart after upgrading from Debian11 or removing some autostart configured by some application that added a .desktop file to /etc/xdg/autostart/

OBSERVED RESULT
Only shows autostarts configured in ~/.config/autostart/ are listed

EXPECTED RESULT
Finding and being able to manage all autostarting software (except plasmashell) under "Autostarts"

There could be a categories for user-added applications (those in /.config and maybe also all non-default ones), default/system-applications (these could even be hidden by default), and deactivated/dysfunctional entries (see https://unix.stackexchange.com/q/774058/233262 and these could also be hidden by default).
There could also be some organized information for the entries such as which software it launches in the Exec command (and maybe some info about that package) or what it's supposed to do (mainly if it exists, the Comment in the .desktop file).

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: Debian 12
KDE Plasma Version: 5.27.5
KDE Frameworks Version: 5.103.0
Qt Version: 5.15.8

ADDITIONAL INFORMATION
This is really important and would make KDE a much more attractive DE.