workaround:
I've created 6 User group promotions, to apply the promotion Add user to user groups: Unregistered / Unconfirmed while user state is each of the options other than Valid
it only updates once per hour, but that's an adjustable cron setting .. works better than nothing
very similar to (resolved) https://xenforo.com/community/threads/user-group-display-style-priority-not-being-followed-if-user-group-title-or-banner-text-fields-are-empty.198796/
User title override, User banner text, and User banner styling for group Unregistered / Unconfirmed do not work...