SUMMARY
When using a system with a touchscreen, but no mouse connected, using a finger to scroll down the page of desktop effects scrolls faster than it should, and it's impossible to scroll back up - the page properly drags up, but once you remove your finger the page springs back down past where it was. Once you plug in a mouse the problem corrects itself, and continues to work even after the mouse has been disconnected again - until closing and re-launching System Settings.

STEPS TO REPRODUCE
1. Launch System Settings on a system with only a touch screen, and no pointing device connected.
2. Navigate to Desktop Effects page
3. Scroll the list using the touch screen.

OBSERVED RESULT
Scroll position bounces around erratically, always ending up scrolled further down than expected, and never allowing the list to be scrolled back up.

EXPECTED RESULT
View scrolls like every other scroll area.

SOFTWARE/OS VERSIONS
Operating System: Arch Linux 
KDE Plasma Version: 6.0.2
KDE Frameworks Version: 6.0.0
Qt Version: 6.6.2
Kernel Version: 6.8.1-arch1-1 (64-bit)
Graphics Platform: Wayland
Hardware: HP Elite X2 G4

Sorry this one is probably going to be difficult to reproduce and test, considering most devices like laptops and SteamDecks with touchscreens have built-in pointing devices that can't be easily disconnected. And I'm (so far) only able to reproduce this if none of those are connected. Feel free to let me know if there is anything I can do to help, since I do have access to appropriate hardware.