Reposting here just to make sure I put this in the right support bucket.
Known and acknowledged issue. Fix is on the way.
https://us.forums.blizzard.com/en/wow/t/ui-bugs-with-m1-macbook-pro/731802/18
Awesome. I notice all of a sudden I get way better frame rates. There are bug here and there, but man it runs so smooth! I and hyped!