depends on the game! some have great, nongrating music but hearing it replay for the 49th time, it wears on your brain. (´-ε-`)
i'm in the same boat of turning bgm down, system sounds down, max volume character voices and med-high ambient noise. d( ᵘ ꒳ ᵘ ✼)
If there's an option of music silencing or quieting when a character speaks, I always enable it. I prefer to hear the voices than the beeps and boops some music choices seem to favor. It might just be me but there's some music that has a certain tone that rings through straight to my brain no matter how quiet I make it. (´・д・`)
if i play my own music, i get distracted by it and trying to find one to fit the tone of the story which will just take me out of the immersion. (•̀o•́)ง