Could be a coincidence. Reinstall the OS and don't automatically migrate your data.
Which process is running your CPU? The identifiable UC processes are using minimal resources on my MBP. What happens if you just kill the processes in Activity Monitor? Do they start again and use the same resources (did you turn off 'automatically reconnect to Mac or ipad' in the UC prefs before turning UC off)?
Hi amok-san and darngooddesign,
Just to let you know ... I've sent a bug report to Apple concerning the following scenario that perhaps may be the reason why you are seeing significant resources being consumed by UC.
I began by using UC on three MBPs, an M1, an M1 Max, and an i9. I then returned to an office with two of those computers that was roughly 75 feet horizontally away, one floor up, and probably four walls between the first location and the office; that is to say, one of the three MBPs was 75 feet, 4 walls, and 1 floor away from the other two MBPs. When I attempted to use UC to connect the two local MBPs, I found UC would not work between the two local MBPs even though the third distant MBP was not seen by the two local MBPs. Also, UC was now chewing up 100% of a single CPU on both local machines even though it would not connect those two MBPs. All three MBPs, however, were still connected to the same WiFi LAN, but the two local machines were out of Bluetooth range of the third distant machine.
I tried killing UC processes, using launchctl to switch UC on and off, rebooting, etc. but nothing worked. Finally I came to the following conclusion:
It turns out that even though they were out of BT range and the two local MBPs could not "see" (by UC nor display sharing) the third distant MBP, UC was expending 100% CPU time on the two local MBPs attempting to connect to the distant third MBP even though it was out-of-range. I had to go back to the distant MBP and switch off its UC (System Preferences -> Displays -> Universal Control... -> (uncheck) Allow your cursor...) and this allowed the other two local MBPs to reconnect via UC. An error message informing me that this was the problem would have been nice, but there was no indication of what the trouble was.
Solouki