Could you check what’s the authentication plugin for the user you’re trying to log in as?
E.g.:
mysql> select user,plugin from mysql.user;
+------------------+-----------------------+
| user | plugin |
+------------------+-----------------------+
| mariaex_user | mysql_native_password |
...
The default auth plugin for mysql 8.0 is caching_sha2_password and so if the user was created before you changed the default auth plugin that’s probably the issue.
