Universal Control is broken - Works for a second occasionally and then nothing

If it worked, I'd love Universal Control.

It worked quite well for the longest time. Now, it is intermittent at best. The last few times I attempted, the cursor moved to the iPad for a second and then vanished. The active cursor moved back to the MacBook Air, and I'm unable to move it back to the iPad.

A few minutes later, I was able to move it over again. It stopped moving as before, but this time it left behind the small circle cursor on the iPad screen. It appears that some connection is possible randomly, but it never lasts more than a second and is extremely flaky for some reason.

Yes, I have read the other complaints about this common problem. I've rebooted both devices, I've made sure they are on the same network, I ensured they are logged into the same Apple account, both OSes are updated, and so on down the list.

Any clues as to what is going on?

Sidecar does work flawlessly, btw.

iPad (10th generation) & Macbook Air (M1). Latest OS on both. There is no problem using Universal Control between my MB Air & my Mac Studio (M2).