Have you looked into nostr? It offers most of the same features of Mastodon except that:
- Your identity is not tied to your instance. If your instance closes up shop, you keep all your followers, followees, DMs, etc
- You can send encrypted DMs, so your instance admin can't read them
- Cool tipping functionality so you can tip people if you like their posts. Or don't use it. It's optional.
- Most nostr clients have some built-in filtering functionality to block out things that are NSFW, crypto-related, etc. Different relays have different moderation policies, much like mastodon instances.
You can run your own relay of course.