Oh gawd. Clean install. You have no idea (you probably do) how much I'd have to install 'fresh'. It would be an entire day of just installs.
![Frown :( :(](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
Thanks though, under consideration.
Had to do clean install with upgrade to Catalina Oct 2019. Yes, a day, yes it worked. Takes an hour or two to install, same with a new iPhone but still the customizing and getting working.
There's a lot of change that has happened with where and how the system is laid out. Migrating can introduce problems. Step #1 might be to use new Mac "as is" to insure everything works as it should. When troubleshooting and diagnosing - introduce one change at a time. Urban lore, wait 3-4 months for issues to surface in hardware/software, even production changes.
Ran across two sites with m1 Big Sur compatibility chart - native, Rosetta 2, version, the state of support.
There are issues with pre-11.1 with reinstalling, erasing, recovery, which is terrible, and with ability to create a second system volume - handy for testing a system. *Sometimes* just a new user account to see if a problem lies in user account, often in home ~/Library.