I despise litigation but perhaps that's the best solution to solving this - especially when it also involves lies and blackmail. Maybe people will think twice if there are very real consequences involved.
The endgame will be that only rich people can afford justice once you need to finance the real consequences and the due process and everyone and every procedures involved. Really, sometimes, I believe the only winning move is not to play.
What I've been doing is stop saying anything remotely controversial or specifically related to people or society and definitely I don't interact with tweets by socially-aggressive people.
For everything else, I just use throwaways.
And I hate that my name is traceable back to my time in 2007 because it was so cool to use the same unique name everywhere. Nowadays Facebook, Instagram, LINE all are "serious" accounts but all have different IDs and lack my last name.