I have been frustrated by Windows 11 inability to consistently use my preferred theme, especially during the Night-Day theme changes. To this end I found a way to create a Desktop shortcut to the theme I want to use. Far easier than constantly opening Preferences. Create a Shortcut to the saved desired theme in this folder:
%localappdata%\Microsoft\Windows\Themes
Update:
This is no longer working for me, as it is with Windows and its inconsistency.