I find it's easy to not notice that you only got "nice" or "meh" on a single note, finishing the whole level only to realize you didn't get the blue or red star ranking. Rather than just changing color at certain arbitrary numbers, I think it would be a really nice QoL change to have it change color to indicate the worst accuracy note-hit you've gotten all level so you don't waste time when aiming for the best ranks.

Purple = All Perfect

Red = All Great or better

Blue = All Nice or better

Orange = 100% accuracy

White = Less than 100%