No. Docker compose, if you want to get technical not just "docker", with MariaDB. When the cron job runs docker-compose down it backs all the subdirs up, including the full DB directory. (Probably not a cheap plan for a heavy-use site, but for my family it's a normal thing for day-to-day to have no changes.)

Interesting that you comment about SQLite being a problem. I am not a heavy user of Nextcloud, but I haven't had the operational problems many people report here; I wonder if that's correlated to using SQLite.

That's an interesting idea - I guess when it's all shut down, simply copying everything can't really fail or break anything.

Since I'm using the same setup (docker compose for nextcloud, MariaDB, and some other stuff), maybe I should really look into that option, thank you!