I used to have a 11" MacBook Pro running Big Sur but upgraded to the 24" iMac. I already had BiaB on the MBP. I used the auto transfer between the two computers, the iMac had Monterey already installed. Everything went smoothly and all setting were transferred to the new Mac. BiaB worked fine, as did every other piece of software. I did upgrade to version 515, and again had no problems.

Should you upgrade, hard to say, that's a choice you need to make yourself. As there is not a lot of posts from other users having problems on this thread I would suggest nobody else is having problems either.

GarageBand of course will run as it is an Apple product, so no problem there either.