> Oddly enough he recently promoted a guy who has been fucking around with LLMs for years instead of working as his right hand man.

Why is that odd? From the rest of your description, it seems entirely predictable.

That's directly lethal, in a limited sympathy with engineers that don't immediately head for the exit sort of fashion. Best of luck

The most experienced people quit, yes. There's some other not as experienced who are left, but seeing how a noob with less seniority and a large ego is now their boss, I expect they're proof reading their CVs as well.

I think under current management immigrants have no chance of getting promoted.