Mine ran hot too for several days due to all the indexing. If you have a large Photos collection and icloud folders, it can take several days of indexing. I finally got it to quit by turning off the power saving features and let it run full throttle for about 24 hours.
Reinstalling MacOS or time machine restore restarts the process all over again.
Wish Apple would be more upfront notifying the user rather than making you watch activity monitor to see all the extra syncing hidden apps consuming all the CPU cycles....
After that my MBP ran much quieter with much better battery life. Even when plugged into a 4K monitor.
Too late now it's gone back.
But I'd had it 3 weeks and there were no issues & then all of a sudden this cropped up and wouldn't stop; even after a full reinstall and left for a few days it was still running stupidly hot!