This doesn't mean, OpenBSD is bad. It's main focus is just not speed and performance. It's main focus is security, clear and clean structure and good documentation. That's perfectly fine.
@Haydar OpenBSD just isn't that good of a desktop OS IMHO. But so many people try to force it to be one. OpenBSD for servers is a great choice. As you already said: secure, excellent docs, and sane defaults. If you don't want to run the fancy new stuff OpenBSD is an great choice.
One of the first Mastodon instances, there is no specific topic we're into, just enjoy your time!