I have noticed that when removing Gust Additions from Windows 11 VM, the VM's screen/display gets messed up and I won't be able to do anything without a VM reset/restart.
This does not happen in the case of Windows XP or 7, neither does it happen on various Linux flavours.
The Host OS Windows 11 Build 26100.3037
The Guest OS Windows 11 Build 26120.2415
VirtualBox Version 7.1.7 r167389 (it comes with Guest Additions 7.1.7 r16730, but I also installed GA 7.1.7 r167389, but no change in this regard).
Laptop Screen resolution is 4K.
This has been happening for some time on other versions of Windows 11 Guests, as well. To correct it, reset/restart the VM and reinstall Guest Additions.
However, this behavior does not happen if you install Gust Additions without uninstalling/removing the current one first.