Mewing isn’t some special recipe for getting a good jaw. It’s basically just the normal way you’re supposed to position your tongue.
People who keep their tongue in random positions and breathe through their mouth often do it because enlarged adenoids make it hard for them to breathe through their nose. And if they’ve been mouthbreathing since they were like five and their parents never took care of it, IT’S OVER. Even Jordan Barrett’s son would end up a chud like me.