JSX isn't and hasn't even been necessary to use React. The first version of my company's site didn't have a build step and called createElement manually.

And in the decade I've been writing for React, I've never used the React compiler. But saying that it's proof that it's not JavaScript it's like saying that V8 is proof that JavaScript is too complicated because otherwise it would be fast enough not to need a JIT.

And all those rules? You don't have to follow them either. Use class components. They're still there, and they work fine.