I know the "Chinese Zero to Hero" program from watching some of the YouTube videos, but I didn't find it particularly appealing to me for several reasons, so I not only didn't purchase his courses, but also didn't watch the vast majority of the videos available for free.

It is indeed a course based on the HSK. And that's a problem. Even if you need to take a language test, my language learning philosophy has always been: first learn the language to a particular level, then study for a test. To boot, in my opinion HSK is just not a very good structured test.

Secondly, this course uses too much English, even on upper levels. I actually wrote a comment on YouTube about it, something to the effect that with many other languages at the intermediate level at the latest we start to use the target language exclusively. To his credit, he responded to this criticism, and he even conceded that HSK-6 is not the "hero" level. Shortly after, although I don't think my comment was a trigger, he probably has already thought about it, he uploaded a video in which he said that he wasn't quite happy about his HSK-5&6 courses and announced some new courses.

It's not his fault that he isn't quite happy with his HSK-5&6. As I was saying, HSK is just not a very good test. Well, it is made in China and by a government institution, what did you expect?