After a week with the current version, including a registry cleanup, I had no crashes in Outlook. At the moment it seems to be running stable.

I have installed the update now @JochenSaalfeld and will observe the behaviour over the coming days.
Somehow my Outlook in combination with the plugin messed with the registry. I could only permanently re-enable the plugin after removing all related registry entries in HKEY_CURRENT_USER. Otherwise it would not load on start anymore even if activated by me.

I am connected via IMAP. Sometimes Outlook also crashes when I handle a message that is in a local inbox not directly associated with an account. It may be relevant that I have two IMAP accounts configured that run on different key pairs and all messages are shifted to a local inbox on arrival.