It is good to point out this alternative is 90% likely going to be a rugpull on "nice cosy 90s style social network" by systemic factors. Regardless of the intent of the owner.

I just realised federated helps re. censorship but not privacy/secrecy needs.

It's not a rugpull, because there's nothing invested by users.

Again, there's no alternative that meets your original criteria let alone your additional ones.

I mean.. yeah. That's why no "Facebook like 2007" social networks have happened since. It would have to be run by someone with a lot of built up trust in order for people to trust it in the way that people did with Facebook. The world has been burnt.

If say, Valve started a social network I would consider using it because they've had decades to screw up Steam and they haven't. It is a bit outside their wheelhouse though.

This random guy though?

Steam friends chat is already my primary method of contact for certain people, having very little to do with playing games together.