Accessing my email via email apps using app passwords does not work, the authentication fails. My main password works, no problem. I would prefer to use app passwords though so that I do not expose my main password unnecessarily.
I didn’t meant to say you couldn’t file it as a separate bug too. It can be useful to set separate imap/smtp password differing to the normal account. This is a feature-request inside nextcloud/mail - but as said, murena is using rainloop or its successor snappymail