Stealth is the new ranger: something to complain about, disconnected from the actual rules.
I think people tend to make too much of the complexity of Stealth when discussing it, and I imagine in play they just roll Hide versus Seek.
2024 D&D has generally bad organization, with incomplete rules in 3 places between 2 books. But the actual rules are pretty simple and perfectly usable.
All that said,I still would not have used the Invisible condition to define "hidden." It's unnecessary and just invites confusion. And I think it is counterintuitive to say that if any single enemy finds you, thay all magically do.