Have you considered PostgreSQL? MariaDB would probably be fine and has the advantage of having a lot more tutorials on the internet (makes it a tiny bit easier

Have you considered PostgreSQL? MariaDB would probably be fine and has the advantage of having a lot more tutorials on the internet (makes it a tiny bit easier to get started), but Postgres is the best open source database there is (in my opinion at least). I don't bother with MySQL/MariaDB for my own projects anymore (I started on it 10 years ago). I only ever use it if I'm installing something that won't work with anything else.