That's a shame. It seems to me that we are in a frustrating situation where there are probably clever ways to solve the problems created by social media. But because launching new social platforms requires solving a difficult chicken-and-egg problem, we don't get very many chances to try anything new or innovative.
Another way of putting it is: Occasionally people will speculate about ways to fix issues with Twitter, reddit, etc. Such speculation feels fairly pointless, because there is little evidence that the moderators of those platforms are listening to suggestions, or even care about anything besides profit maximization. Without much demand for improvement ideas, the supply of such ideas tends to dry up as well.
If anyone else is in this situation of desiring to sunset a social platform, I would encourage them to run a contest. People can enter your contest by submitting plans for how to revitalize the platform / a genuinely new direction for social media. You judge the entries, pick a winner, and the winner takes over administration of your platform so they can try out their proposed new direction.