I feel like Windows 7 fills the sweet spot between the seemless UI of the 2000/XP era and newer versions. Windows 10/11 could top that list if Microsoft had bothered to create a proper UI instead of just slapping some material design on a handful of apps, while everything else is still basically 2000/XP. Then again, GTK2/3/4 can be almost as bad.
The true arch experience.