I have 3 monitors @ 1920x1080, 100% scaling, small icons. My video card is a NVIDIA GeForce GTX 1050 and I'm running studio driver 472.47.
I just discovered that if I set the icon size to medium or large, they re-arrange properly, but not if the icon size is small.
On Windows 11, I could not reproduce what you are reporting on my 2 monitor system:
If you unplug all but 1 monitor, does it still happen?
You did reboots after each install, yes?
What is the exact version of Win 11 (winver.exe) you are running?
Do you have 'auto-arrange icons' \ 'aligned to grid' on, and if not, does it change anything if enabled?
Stardock Support Manager