Years ago I had found his channel and liked it, and then some video (I don’t remember the title or even subject at this time) came up on a subject I happened to know quite a bit about. He got to some point in an explanation, bungled it, and then hand-waved it away, saying the details were unimportant.

Stopped caring about anything he had to say after that, and I also then realized that there was a an entire genre of “person with no actual expertise reads Wikipedia articles and explains them with good lighting and high production quality.”

Most things? That's a really strong claim, do you have anything to back it up with? Just a couple videos here and there wouldn't cut it, given how strong your claim is.

For what it's worth I watch his videos and he seems to touch on incredibly valuable topics I would never hear about otherwise, like [1].

[1] https://youtu.be/2tuS1LLOcsI?si=b3mS0meBazL0RlcS

Do you have a reputable sources to back up your claims here? Johnny cites sources pretty consistently.