I did a direct update from Catalina 10.15.3... first changed from Clover to OpenCore and then updated from the App Store. Switching to OpenCore is what took me the most time, quite a few things to figure out before I got it working properly.
The Big Sur install took a long time to go through, about 2 hours(including several restarts), but once it was finished, it has been working great(including USB3, WIFI, BT, Ethernet, Messages, etc). Probably could have gotten it done quicker, as I wasn't at the computer the entire time, but still very slow install, several times I thought it had got stuck, but in the end it went through... so be patient...
I like Big Sur, like the design, and feel like some things are snappier, and Logic Pro seems to load faster... Logic is working great, with only a handful of plugins(out of my ca 1000 plugins) not being compatible(Gullfoss, Glitch2 and Slate VMR have UI issues, but the other Slate plugins seem fine).