Many people point to the bad spelling and grammar of these powerful, abusive people and they say wow, that's a flex.

My own reaction is more like these people are stupid. It's not power that makes them write poorly. They're not capable of getting it right.

Look at what Noam Chomsky wrote to Epstein as a contrast. Multiple paragraphs and usually coherent. He makes Epstein look dumb. (Which he was.) I don't support what and to whom Chomsky was writing, but he is better at writing.