Lots of new people on fedi, indeed. Still, pay attention to the people responsible for hosting your instance. You may or may not agree with their moderation practices, and they might be malicious.
I don't necessarily recommend self-hosting as it requires time and dedication, and comes with security implications. But a single-user instance might be what you want.
Also, "private" messages are not so private given the context of federation, that is until they will be end-to-end encrypted.
Just another single-user instance.