Also for a lot of people, their social circle is partly there.

I get that, but at this point I'd actively try to get them to use a different site/app. I managed to move large parts of my friend group and my whole family to Signal. I'm now trying to get some to transition from Discord to Matrix, though moving there has definitely been not as smooth.

It should be much easier with Twitter, there are a bunch of very similar and usable alternatives. You just have to put in some work and convince people with solid arguments and support.