I decided to try Monterey on my M1 MacBook Pro and wish I could get back the day that it cost me. When it was on the machine, most things worked -- with some exceptions that have been discussed in other threads -- but I decided that I'd be better off reverting to Big Sur.
Right before installing Monterey I had made a Time Machine backup on an external drive, telling myself "I could always revert quickly -- what could go wrong?" To make a long story short, I was unable to use Migration Assistant to restore from my Time Machine backup, because the Assistant for some reason decided that my backup was over 650GB in size .... odd since this was the sole backup that had ever been run and my SSD is only 250GB.
I wound up having to reinstall Big Sur from a bootable USB stick (created via MDS running on another machine). I tried to install three times and each time it would hang at the user account creation screen. Googling that problem, I was reminded that you not only have to erase the SSD using Disk Utility, you also have to "erase computer" using another menu in the Recovery environment, and you have to make sure that the M1 MacBook has been removed from your Apple account before you continue. Yes, I "should have known" all this, but it's a horrible process.
Once the MacBook was booted into the fresh Big Sur install, with the same account name as I'd used previously, I was able to browse the problematic Time Machine backup using the Finder and did get back all my applications, data, a Parallels Windows VM, etc. I also copied various extensions, etc., hoping that I wouldn't have to reactivate all my software.
Unfortunately almost everything had to be reactivated; email accounts had to be recreated; and so on. It's a good thing I'm retired, because this took hours (admittedly, my records regarding license keys should be a lot more centralized).
In conclusion, would-be beta testers beware. I've heard people say that a Time Machine backup will preserve all your settings, but that obviously didn't work out for me.