M1 Studio Ultra
This is most annoying and has been going on for years. You buy a new machine. It runs wonderful for a few months and then everything slows and slows. And slows more. This same story has repeated itself for several computers. I've had this Studio M1 Ultra since they came out and for too long now it is constantly spinning beach balls.
Final Cut is useless with all the micro and macro hangs. It's not just FCP. All apps including the Finder suffer the same challenge. Beachball party. Rebooting and running only one application doesn't solve it.
I tend to be abusive with too many apps running too many windows. If apples aren't meant to have a couple monitors and external drives then just say so and I'll move on to something that can. It's as if something is running major task in background but Activity monitors don't show it. Beachballs happening and 10% CPU load. I wish Linux was viable.
What does your memory pressure look like when you're seeing the beachball?
I know it's a pain, but have you considered doing a clean install, i.e., wipe the thing clean, install a fresh OS, and install your apps by downoading fresh copies from the vendors (rather than using Migration Assistant)? When I do this, it takes me a weekend (which is why I haven't done it in a while!).
I get that you won't want to create all app profiles from scratch, and that you might want to copy over some of your old app profiles, but it would be best if, for the simpler profiles, if you copy down your preferences (maybe print out some screenshots) so that you can recreate them from scratch.
Though if you choose to do this, you might as well wait for Sequoia (and probably best to wait for at least 15.2, to give them time to fix the usual new-release bugs).