I've been using MoI4 and MoI5beta on Windows 11 for a month or so,
without problems.

One big annoyance is the News/Weather widget popup on Hover, which happens when the mouse cursor is in the lower left corner of the screen,
near MoI File menu. Google search says that it is not possible to keep the widget, but disable the popup on hovering.
But it is very simple to TEMPORARILY remove the News/Weather widget from the taskbar,
AND also to restore the widget to its lower left corner of the taskbar.
Reboot of the computer maintains the Widget presence/absence status.

https://techdows.com/2021/12/windows-11-weather-taskbar.html
"Disable and remove the Weather Widget icon from Taskbar in Windows 11
Right-click on the taskbar and select “Taskbar Settings“
Under Personalization > Taskbar > Taskbar items, toggle Widgets to off.
To re-enable the taskbar Weather widget, reverse the above step."

Related post, with Taskbar Settings shown:
https://www.groovypost.com/howto/remove-the-weather-widget-on-windows-11/

Apparently this is the first widget, so things may change.
*********

Another, perhaps undesirable, file explorer burden, is the right-click menu, which has moved many operations to "Show more options" submenu. This requires an additional click or Shift-F10, to access the submenu, including using 7-Zip, Notepad++, Cut, Copy, or Paste file.
This can be changed by editing the Registry, but I am not going to attempt that.
Having a submenu may have its benefits as well...

- Brian

Unrelated to MoI:
Crl_Shift+T to restore a just closed website.