Is it possible to have too many email accounts configured in Mail? I’m using a 2018 MacBook, running Catalina 10.15.1, although I suspect this problem came along when I copied my older (2015?) MacBook onto this new one this past summer. I generally leave my email open all the time, but for a long time now when I would return, after being away from the keyboard for a bit, Mail would be completely frozen, ie not responding. So I would Force Quit, and reopen. I would have to use the apple icon to even get to Force Quit, that’s how stuck Mail would get.
I remember you posting at one point about rebuilding an index file, but haven’t been able to locate that information to attempt it. I was also interested in a conversation you were having on the forum that showed a path to a 98GB log file but that file path doesn’t seem to exist on my computer.
I have a total of 34 emails. 17 @mybusinessdomain, 1 @me.com address, 1 @cox.net address, and 15 gmail accounts.