Didn't read the whole post, but not doubting that Big Sur is a train-wreck. On my (personal) productive environment I am currently on Mojave (which by no way is as good as SL, but ok). Once in a while I boot into BS (Big Sur) which I have installed on an external SSD for testing purposes, only to find out it still doesn't do anything better but most of the things worse, is bloated and slow.
Machine is a 13" 2017 MBP - which I am also not updating, because honesty I found all later iterations of macOS not very tempting and mostly you can't downgrade on newer machines.
Machine is a 13" 2017 MBP - which I am also not updating, because honesty I found all later iterations of macOS not very tempting and mostly you can't downgrade on newer machines.