Owner of Airpods Pro and now Max, and initially I would agree with you. First 5 mins of using the Max I thought that the sound wasn't as good as the Pro. I couldn't quite put my finger on why, but after spending longer with the Max, different songs, genres etc, the sound is... fuller. That is the best description I can muster. With the max i feel like I can hear instruments more clearly, more pronounced than the Pro.
With the Pro it feels like there was a bias towards vocals than there is towards instruments, but the Max feels like it is nicely balanced and a lot of the songs I listened to religiously this year, I've picked up on sounds I never had before.