I'm looking for things beyond simple UI/UX changes, mainly because I think Win11's UI is horrid.
As mentioned above, I think the Win11 UI is horrid. It's trying to be the MacOS UI which is hands down the worst UI I've ever used.
Modern UI trends are all about flatness (which reduces discoverability), minimalism (hiding functionality), and dark patterns.
Windows 7 with the Classic theme and task bar grouping disabled was peak UI. It's been downhill ever since.
and removed the ability to disable collapsing.
If I have 3 Firefox windows open, then on the task bar, I should have 3 Firefox buttons, each showing the title of the web page they're on, so it should only take a single quick glance and a single click to switch windows.
The current behavior did not begin with Win11, but Win11 is the first Windows to force it. Even Win10 lets you configure it to behave more like Win7 and before.