I would trust the ears of people in here more than I would a low quality YouTube video. I have to admit that I didn't watch the whole video because I tend to stop reading/listening to reviews that are mostly subjective, rather than objective. Having said that there are also potential scientific reasons (though I could have missed it if he provided the information).
First, it is impossible to record exactly what is played back (it will have a flavor of its own just like every different DAP does, as well as having some degradation). It is like making a copy of a copy. Not to mention YouTube is lossy, compressed audio, which is more degradation. Also, what source is he using, did he do a volume match, what equipment did he use to record? There are just too many variables that could cause anomalies.
All of that being said, I wish I could help you, but I only have the OG P1, the Timeless, and the Hook-X (on the way). More money and better sound don't always go hand in hand. If your ears like the cheaper IEM, then you stick to it and enjoy the heck out of it.
I sometimes listen to my $13 CRA over my Focal....