Which is to say... sifting through it is dangerous.
Luckily, some GMs have put together good material, and a lot of it! It's well organized too.
They call it "books."
Yeah, I have a couple dozen of these things you call "books" related specifically to chess ...one of them talks about how the bad the Berlin is for black. Which is the problem with books...chess is a little too dynamic to rely primarily on books for reference.
Opening books become outdated, sure.
And for example, I don't like watching agadmator, but anyone who enjoys watching one video of his every day, over time, will have been exposed to a lot of great games.
So sure, make use of everything available, and that can include Youtube videos (there are GM lectures on Youtube for free. I particularly like Akobian).
He seems like a decent enough bloke to me, can't understand the hate for a fella that's only trying to make a living from (his undoubted) talent. YES, an IM is most definitely talented. Not everyone can be a Morphy or a Pele, an Ali, a Federer (or a Kosteniuk ) etc etc, but they can still be helluva talented at what they do.
I enjoy his content, it's usually entertaining and often informative. I particularly like his 10 minute openings, not too in depth that it confuses and just enough that it gives beginners like me a few opening moves they can feel reasonably confident with.
A decent bloke, a decent player and a decent streamer....but I'm still Team Kosteniuk though.
I'm sure he could have been a GM by now if he'd focused on chess.
Instead he focused on making money, and I don't hold that against him at all. Yeah he's talented... I'm also happy to see he has more Youtube subscribers than Hikaru... maybe if that goes on long enough Hikaru will have to start simping for him!
Then I really might start watching Levy's videos haha.