I want to add Guilty Gear Xrd Rev 2 as a contender for one of my favourite FG soundtrack. I'm surprised I forgot to mention it before.
I only played this game a couple of months back to prepare for Strive, but I was very impressed by a lot of the music. And there's quite a lot of it.
You've got lots of pounding, heavy guitar-laden tracks that play for most of the battles. Guilty Gear takes a lot of inspiration from real world Rock and Metal, so it feels very fitting, though not everyone will be into it.
Elphelt's theme, Marionette, was a battle theme that really stuck with me. Especially that opening.
It's not just all heavy guitar themes though.
Xrd's cinematic story mode and character episodes often play a very different kind of music, some of which were very relaxing beautiful tracks that accompany the character's thoughts about life, destiny, identity, what it means to be human and all that deep stuff.
I get some big NieR/Drakengard vibes from those kind of tracks and I like some of them more than the battle themes.