I’ve had no problems with the normal nextcloud apache container for the last couple years. I lock to a major version and let it update itself on the minors until I feel like like changing the yaml to the next major. I’ve gone from 24 to 30 this way without issue.
Actually, I do have to install the contacts and calendar apps from time to time but that’s only when I want to use the webUI for them, caldav/carddav has always worked.
I host pingvin for people to send stuff to me. To send, usually I’ll just move the file into a folder that exposed to Nginx with indexing and send that link. Otherwise I’ll also just use my pingvin instance.