There is none yet that I know of.
But I think something has to be said as well: the problem with copying to the T the most popular social networks is that those are designed to be deliberately predatory and addictive, many parts of their design is implemented in alternatives without even thinking what it really means for the users, because it has become second nature to us and they also feel good, but are mostly detrimental exactly for that and I’m the first to say that I keep falling for it, spending hours on end on my phone. Think infinite scrolling, instant notifications, etc.
While it’s good to have the option, if we want a healthier social media experience, it doesn’t suffice to decentralize it, we also need to think of at least better defaults, then let the users decide for themselves if they want a more addicting experience