He made the Sibelius one before he'd ever used MuseScore, did the MuseScore one before Dorico/Finale because of popular demand even though he'd never used MuseScore before that, and then eventually got hired onto the MuseScore team because of the strength of his critique, and proceeded to lead the effort to fix all of the issues he brought up in that video. He made the Dorico video no more than a couple months after joining the MuseScore team, and a couple months before becoming Product Manager there. The Finale video seems unlikely to come out now, honestly.

So, only the Dorico video is even possible to be a shill. Also, oh my goodness if he made YouTube videos to raise his personal profile, as opposed to all the other YouTubers who make videos anonymously?!?

Even if that was true (and you have no evidence of it), nothing he said in those videos was wrong. And his video about MuseScore was not very complimentary; he called it a “dog’s dinner”.

But to address the wider point, the same complaint could be made about anything anyone ever wrote anything for money. Since some works written for money have lasting merit, the mere fact that something was written for money should not count against it.