Thank you for your response!
I wanted to clarify the problem I was having with the music volume. The music volume was great for most of the game. It was only when going underwater that I had trouble with some of the louder songs.
Here's a screenshot of ~7 minutes of my video's audio. The white horizontal line represents a good level of volume and you can see that most of the audio stays within that. Every single spike above the white line you see is when the camera went underwater. That's a more than 2x increase in volume in some cases!
I could adjust the music slider in the settings to get good underwater volume, but then I would barely be able to hear the music when above water.
I hope this clarifies the issue I had. I hope for all the best for you and your team.
(Edit: I just wanted to note that in the videos I posted on YouTube, I already edited all of the volume spikes to be under the white horizontal line before posting, so you won't be able to notice as big of a difference if you watch the videos)