If you want to ban something, then ban free social media. There has to be a minimum charge like 100$ or something a month (keep it tax free for all I care), to access any social media service with more than a 1000 members.

How does one start a new social media network in that world? Cover the $100 fee, essentially making it free to use? It would kill any competitors from being created, at least until inflation makes $100 worthless.

Microfiction:

Today, on June 1st 2030, I'd like to announce the launch of the fediverse cooperative, the first cooperative social media platform.

We pay out all our membership fees (minus hosting costs) to our entire cooperative.

To use our servers, you'll obviously have to become member of our cooperative, paying $100 a month in membership fees, and earning $99.50 a month in dividends.