Migration Assistant Issues

I'm trying to use Migration Assistant to move from an Apple Mac mini "Core i7" 2.6 (Late 2012) running Catalina (latest version) to a new Apple Mac mini "M1" 8-Core 3.2 (2020).

My process:

1. reboot the i7
2. Using disk utility, erase a 4tb USB drive Mac OS Extended (Case-sensitive, journaled) 
3. Set this for Time machine backup, perform backup. Eject safely, plug into M1 Mac mini.
4. Boot the m1 mac, run through the set up, creating a new admin account.
5. launch migration assistant, bring over all of the data available, including three admin accounts
6. once completed. reboot the m1 Mac mini

Once this has completed, I am trying each of the 'admin' accounts. Two of the admin accounts open flawlessly, one hangs after entering the password (spinning ball).

Things I have done to alleviate this:

1. erase/recreate the time machine backup
2. remove all login items from the affected account and then recreate the time machine backup
3. erase/restore the m1 mac mini, update with the above
4. boot in safe mode on the m1 and then try to log in

On each restore, accounts #2/3 login fine, but account #1 still hangs when trying to log in.

Is there a different way I should try to accomplish this? Or is there anything else I can do to 'clean' the affected account before bringing over? Instead of using an external hard drive, would a migration via network be better?

Any suggestions would be appreciated.