My 2024 iPad Pro gets stuck trying to back up to my Mac

I prefer to back up to my Mac Studio, not iCloud. I don't sync/back up my iPad Pro very often, but I decided to do it last night. There are a few problems.

1) a GENERAL problem, which I had with my old iMac and old iPad as well, was that it would always default to "back up to iCloud" and even though "automatically sync when the iPad is connected" was checked, I'd always have to manually start the backup. This is still happening with my new iPad and new Mac.

2) The last time I backed up my iPad was January. I hooked it up last night and told it to back up. Hours later, I unplugged the iPad to do some stuff, and noticed that the sync screen (or whatever you call it) was still going. The status bar at the bottom had only moved about 10% across, and most of the buttons were greyed out. I couldn't shut down the Mac because "it was in the middle of an iOS operation" I had to "eject" the iPad, even though it wasn't physically connected, was turned off, etc. Today I hooked it back up and...still in progress. I deleted the backup, thinking this might make a difference, but it doesn't.

If you look at the screenshot, this is what I see when I hook up the iPad. Anything that is greyed out is inaccessible. If I "eject" the iPad and then hook it up again, this screen will appear again. Exactly like this.

Even though the bullet for "back up to iCloud" is selected (which keeps happening as I mentioned in #1 above) I don't know if it's actually trying to back up to iCloud I would expect to see some kind of movement, or ability to cancel if it was actually doing anything. Any ideas what is happening? Or how I can cancel this stuck backup process and start over?