In my experience I saw the complete opposite of "juniors looking like savants", there are a few pieces of code made by some juniors and som mid engineers in my company(one also involving a senior) that were clearly made with AI, and they are such a mess that they haven't been touched ever since because it's just impossible to understand, and this wasn't caught in the PR because the size of it was so large that people didn't actually bother reading it.

I did see a few good senior engineers using AI and producing good code, but for junior and mid engineers I have witnessed the complete opposite.