The partial recycling makes more sense; TOS had its own defined score and in 1979 comes this new music that has a big "Wait, wut?!" reaction. In TNG, it feels at home instantly and perfectly.
It's fun to hear where that, from a strong starting point, how it descends into a surprisingly generic affair, also predating Orville, Galaxy Quest, and sequences that almost borderline parody (the sharp turn starts at 0:43). It just doesn't work as a main theme. His episodic scores, especially seasons 1-3, Next Phase, Generations theme overture (and numerous incidental moments within) et al, are
sublime... but this as the main theme? Not as such, but it is cool that some of that theme was repurposed into episodes.
A few youtube videos seem to cover some of it all, but there's so much background muzak and stupid camera angle changes and jump cuts that you wish there could be an audio filter to remove the backing noise... and then not gawk at the screen to make listening to the content, that stuff as to why we're there in the first place, the actual priority. We want information, not a song and dance with camerawork better suited to fictional drama than real life documentaries where the focal point of the speakers should have any prominence.