I purchased a brand new 7 series watch on Jan 22, 2022. My Memoji face page keep freezing too. At first, I had to do a hard reboot but then my watch started rebooting itself. It started to happen more frequently that my watch keep freezing when it sets on the Memoji face page.
I even unpaired, erased all info, and reinstall it. Still having the same issue, I decided to return it and get a new watch. It’s been a month and now my watch is acting up again when I set it to the Memoji face on my watch. I'm not sure if there's a bug with the software or something is wrong with my watch.