My daily driver computing timeline is something like Win3.1, 95, 98, ME, XP, OSX 10.4-10.11, then some combo of Ubuntu/Pop_OS.
I think Windows peaked with XP and macOS with Snow Leopard, with the caveats that Spotlight-like searching in both was primitive/nonexistent at that time and would have been a great improvement, and XP didn't have virtual desktops.
That 2001-2006 era featured systems that had learned a bunch of lessons from 10-20 years of mainstream GUI computing, but hadn't been consumed by feature bloat and a bunch of Internet connectivity and convergence stuff that I'm not interested in.
XP's design was apparently polarizing but I loved it. I was in a modding phase at that point and loved making my own themes.