I'd just like to add more stuff without making the page unnecessarily long, and also I think it'd be nice to directly hyperlink the OST.

I'm confused about what you are asking for, as I was under the impression that [[Girls Last Tour Music]] functioned well as a page for the OST.

Do you want a page dedicated to background music only? Or just the current Soundtrack page to be reformatted to allow for more information to be added easily?

"a page dedicated to background music only" is what I was thinking. The current version functions well, but I intend to add quite a bit to it in the near future. I can do it tonight, but if you think it's unnecessary I can just add the information to the page now for now, and we can see how it looks from there. I feel like the page would feel a bit unbalanced, but that's just my opinion, and could be completely inaccurate

Ah, I see what you mean. I made that page with the intention that (eventually™) extra info could be added to each song by adding a new column. I do believe this approach would work for limited information (e.g. composer(s)), but if you plan to add much more than that, I agree that more space may be necessary to prevent it from looking bloated and all that.

While I do quite like the idea of having the whole OST on one page, with the more important tracks (the OP, ED, etc.) with more information on their own article; I am not entirely opposed to having a dedicated page for BGM.

The only problem I would really see with this would be that having it on its own page would hide the extra info a bit, since you would have to go to another article to access it.

I think that if adding the info to the existing table would be unsightly, it would be best to simply create a collapsible section on the existing page for the info you plan to add.

That being said, I'm fine with any of these approaches in the end, and you have my full support for whatever you deem the best fit.