I was just laying in bed and thought I could do some research on how to run #Nextcloud on Docker before going to sleep.
Roughly 30 minutes later I have an all-in-one Nextcloud up and running, integrated to my Nginx reverse proxy and reachable through my subdomain with SSL certificate and everything! What?
Now I just have to migrate my #NextCloudPi users/data to this, but the docu is incredible:
https://github.com/nextcloud/all-in-one/blob/main/migration.md

Thank you so much, @nextcloud!!