It starts to grind you down when you’re dealing with multiple users per PC and unmanaged PCs from a bunch of different sources. Propagating start menu changes to all profiles post install is a hassle in 10 & 11. Sysprep is a lot less useful for setting up the defaults pre install now. The out of the box install process is smoother these days without as much waiting to click through various stages but the post install environment reduces your quality of life with a bunch of clicky fiddling.

Would Explorer++ Portable run in your environment?

From the days of DOS till today Windows 2000 is definitely my favorite, the most cohesive, straightforward and consistent experience. For now I just hope software will keep supporting LTSC through till the end of support.