Having used Big Sur for ~12 hours now, most of the changes feel fine.
BUT the one really irking me is the huge horizontal space in the menu bar now.
It's not so bad with the text menus, but all my installed utilities on the right side are "double-spaced". In fact, several of them have disappeared because they don't fit anymore (until I switch to an app with fewer text menus).
What the hell, Apple? At a minimum you could reduce the spacing if things don't fit, rather than just hiding them.
You may want to look at Bartender[1]. You most likely don’t actually use some or even many of those menu icons very often. You can hide the ones that are just clutter in a secondary menu/bar. I originally got it to keep the icons I do care about visible on a laptop screen, but I still use it even on my huge 4K@1x screen to hide distractions.