No one said a single DB. You can have multiple DBs in a single container, and then use something like databacker/mysql-backup container which solves the complexity of multiple db backups for mariaDB and MySQL

I used a GL.iNet Opal to do exactly this while travelling.

After starting with X-Men characters and quickly running out I moved to Star Wars planets as there are a lot more of them

I can’t recommend Migadu enough. I’m on the $99/year plan and have dozens of domains and clients with their own domains too, it’s easy to manage and does everything I need it to.