Yup. I'm working on something, but it also has some privacy issues as well.
The problem is that the more privacy you have, the more people will post illegal and spammy stuff and the less monetizable the platform is. The more free speech you have, the more moderation costs. So social media companies will generally lean toward less privacy (so more ad revenue) and less free speech.
My focus is on p2p and user-generated moderation, which tries to solve two problems:
instance hosting costs - near zero since data is stored on user devices; you can host a mirror to help
bad mods - automatic moderation - if user A mods like user B, user A will trust user B more and posts they filter will filter for A
But the automatic moderation thing requires public information, like mod reports, categorization, and votes, so it's not going to improve on lemmy in privacy. Anything privacy-respecting would require too much work from users (they'll need to both consent to trust each other). Maybe I'll be able to add it as an option.
But even if my system is perfect (it won't be), it's unlikely to beat something like Twitter or Facebook due to the network effect and sheer amount of engineering and marketing resources available.
Imo, lemmy is good enough for now. People like me will be working on stuff behind the scenes, so if lemmy falls over, hopefully we'll have a ready replacement.