A couple other things I've thought about, more on the social media angle, are (1) starting a personal web site again, and (2) a different kind of social media site. For (1), I've already got a little VM that runs my email and some quickie web apps I threw together. Why not stand up a personal site too, like a lot of us used to have, where I can share all the stuff I'd normally be putting on Instagram, etc.? Obviously that's adding friction for folks too, but I'm less concerned about that stuff getting ignored.
For (2), and bear with me because this is going to sound a bit woo-woo, I think a social gratitude list could be really powerful. Maybe not a big hit, but definitely powerful for people who would use it. I say this because I used to be on an email list with some friends where everyone would write ten things they were grateful for that day and then send it to the list. Now, if this is not a practice you're comfortable with, you're probably dry-heaving right now; I did too at first. But once I got past the fact that it's not very cool, I found that it was a fantastic way to keep up with folks. (That's in addition to the mental health benefits, which I think are evidence-based but I'd have to double-check that to be sure.) Amazingly, I didn't even notice a tendency for it to degrade into performativity or attention-seeking. Overall I just think it would be a structure that would enable some of the positive aspects of social media while discouraging or eliminating the negatives.