The only real solution to the abuse of anonymous protocols is to stop using anonymous protocols and use protocols where clients can be held accountable. But that's politically nonviable in the West.
The correct approach is to deanonymize reasonably "public" online behavior. This is the only way to hold abusers accountable, and, ironically, democratize free speech.
1 person, 1 voice.
Not 1 rich person, 100 troll accounts.
You're right that gating speech behind money could potentially be bad and make problems worse but I only offered that as one suggestion. Instead of or in addition to using money, you could perhaps make a system that uses some type of karma/reputation for instance. Those could still be done anonymously.