I think there's plenty to learn from it, but there's two big problems when applying his approach in a more generalized way:
a) The youtube market is not like other markets, his strategy is successful because (among many things) the youtube algorithm promotes frequent posting. He knows youtube very well, but it's clear from his other business ventures that he's not good in other markets. I don't think you can translate ALL the stuff there into other markets.
b) There's a lot of unhealthy stuff mixed in with the parts that seem like they drive his success. If somebody does X, Y and Z and gets insane levels of success, they may not realize that it's X and Y driving the success, and Z is actively harmful. But I guess it depends on what you consider "harmful" - some might think "harmful" means "hurts the bottom line" and some might think "hurts those lowest on the rung". Either one of those might be true. It's like people who think being an asshole like early Steve Jobs is the way to be a successful leader, when he arguably achieved more lasting impact when he mellowed out.
With that context, I think some of the critiques you mention have substance.
"He's making low value content" -> I think this is true, because he's optimized for the market he's in. I think it's a legit critique that this strategies may not be sustainable or applicable to "high value content". He even expressly says this: "Not the highest quality videos.. It’s to make the best YOUTUBE videos possible."
"the culture of the company is horrible" -> I absolutely think this is worth talking about, and I find it hard to see building a long term company on his approach. The myth that you need to push people to breaking points to be successful is poison.
"he's a fraud/it's more luck than skill" -> Well anyone saying that is just wrong. He obviously is very good at what he does.
Personally, I don't think it's a good long term business strategy to depend so much on a single larger company, one who has a history of changing the algorithm without warning or explanation. But it's a good, but painful, short term strategy, and he will come out of it perfectly fine whenever he suddenly becomes irrelevant. But there are others who won't/haven't come out with much, and I think it's good to have a discussion if this is right or not.
But there are good things there, the critical components, the importance of communication. The direct feedback of "You are my bottleneck" is good, but it easily could turn into passive aggression and ways to pass the buck. I'm sure there's plenty of low quality comments here, but don't just write off all criticism as virtue signalling or whatever. There are def lessons in here, but that doesn't mean it's all above questioning.