hangs at "Select the apps you want to use with this account:"

I experienced the exact same problem.

I solved this by going to the "Internet accounts" from the system preferences.

I noticed that I had an inactive google account, once I activate it, Mail was automatically hocked back with gmail.

Hope this helps 😉

Check [√] Mail and you are done.

If you want others later you can add them later.

did you ever figure out this problem? i have the exact same problem and none of the suggestions i've seen have helped.

I solved the issue by restarting the mac and also freeing up some disk space

I had the same issue... removing all accounts + restarting my Mac solved the issue.

Now adding them back in.