I started with the yunohost install as well but decided to migrate to the officially supported docker install when I had issues with upgrades or had to wait for the ynh package to catch up. Although I don't want to take your money and bear the responsability of handling the migration, I could give you some pointers.
- Use the official backup and restore documentation as an inspiration
- Use the
-W
option with postgres commands so that you get prompted for the password - Don't use pg_dumpall but pg_dump instead and select the lemmy db
- First migrate to the same version on docker
- Make sure everything is working fine
- Then proceed to upgrading to latest (depending on which version you come from maybe it would be safer to use intermediate releases)
That's from the top of my head but I had to try a few times before getting it right.
Since the fediverse is supposed to be decentralized, if you can host your own server and you feel like doing it, I would say you should do so.