I need help reverting my iMac back to catalina

Why do you want to go back?

Going back is not a simple process. It requires wiping the iMac, reinstalling macOS Catalina, then restore your data from a former Catalina backup. Plus the risk of loosing data is very high, especially if your backup has been updated and/or overwritten by Monterey backups.

check out > https://www.logicprohelp.com/forum/viewtopic.php?t=160354

Most there seem to be happy running LPX in Monterey.