Compressor and Audio Tracks - Catalina and Big Sur - Beach Ball.

When using the latest Compressor (4.5.2) and BigSur (11.2.3) (though this happened in Catalina as well), if I have to turn off Audio Tracks in the source file I get beach balls with every click following. It doesn't matter what it is. I've resorted to just turning off the Audio Tracks last but this is insane.
I have an old MacPro (Trash can design) running Sierra and I don't have any of those issues with compressor. I find myself going to it more often for Compressor jobs, even if my 2019 iMac is faster just so I don't have to deal with the beach ball problem.
Any suggestions?
Thank you.

I use Compressor often and have not had that issue. Just tested, not seeing that behavior. What is the codec of the original files, and what are you transcoding to? Are you simply trying to strip the audio from the video files so they are video only?

Usually the files are ProRes (either 422 or 422HQ) converting to DVD or BluRay. The masters I work with have 6 tracks. I just need the first two when making a disc, so I turn off the other 4, but the second I do that (even just one track) I get a 2 second or so delay (with beach ball) for every other click I do on that file.

It's been like this for some time, even through reinstalls of the OS. Happened in Catalina and then on through Big Sur. But the old Mac with Sierra works with zero problems. I swear, I can't track this down. 

Thanks. 

Are you creating these files yourself? From FCP? Why not export only the audio tracks you need? Just guessing here.

No. The post houses we work with delivers them to me. I need the split tracks to make different things out of them if needed. 

just tested with multitrack ProResHQ as well and though there is a tiny delay when deselecting audio tracks it's not as long as you describe and I don't see the beachball? The QT file I tested is about 8 min long. So maybe with much longer QT files it takes longer and enough the launch the beachball?
Have you tried to reset the render queue and/or repair Compressor via the preferences?