Nextcloud AIO is not the only way to run Nextcloud in docker. For example you can use the Nextcloud docker repository and docker-compose for which there are many examples. I’ve been running Nextcloud this way for many years now without any un-recoverable issues, and no issues at all that weren’t caused by me. Upgrading is also very easy since you simply increment the version in docker-compose.yml and restart the service.
That said the NixOS suggestion from @[email protected] looks really neat and I may try that out soon my self since I’ve never played with NixOS before and it seems like a good excuse to do so.
The really hilarious thing to me is that the NextPush app (unified push provider that can be run on your nextcloud server) is unsupported by nextcloud talk. But it is supported by a bunch of other competing applications.