[oarfish]

If I remember correctly, AthleanX is getting a lot of heat from the science-based fitness community for unscientific advice, though I might misremember here.

However, for those interested in practical science for strength training, I would recommend Barbell Medicine's content (by actual physicians) and Stronger by Science, perhaps.

[Octabrain]

I've personally found that AthleanX has, IMO, good and informative videos but a few ones that sounded to me of looking for the controversy for the sake of views, being the one I remember the most about the "muscle-up being a showing off party trick" which is, based on my years of experience in free running, body building, gymnastics, martial arts and climbing, utterly ridiculous.