Man of Honour
As a long term user of all versions since Vista, I'd say 10 and now 11 is the best balance of visually pleasing UI. 11 actually has a usable dark mode which is ideal on modern displays and desktop environments.Windows 10/11 is such an eye-sore compared to a properly setup Windows 7 aero glass theme and using 3rd party software to replace the UI can potentially cause all kinds of issues, or require redoing, after updates
I have an old folder of desktop screenshots of how each version was set up on my machine at the time:
7:
11 (23H2):
Personally I don't miss Aero, as I favour dark mode over it for Explorer and apps.