Donetick can be self hosted and has a nice UX.

There are forks and they are still accessible. So decentralization works.

Why full disk encryption is important: what happens when you switch servers or providers: can you be sure the disk gets wiped properly?

Or when your disk dies and gets replaced, what happens to the old disk? Will they physically destroy it or just throw it in the bin?

When encrypted, it doesn’t matter; no one will get data off of them. That’s why you encrypt servers.