I’ve argued for color-ratcheting, the ability to change the coloring scheme to make “red” mean whatever your current level of buffer is.
I don’t think @dreev’s screed applies here, for a couple reasons: first, you’ve said it doesn’t apply so much to display preferences, and setting a color is a display preference. Second, color-ratcheting is more like ratcheting than adding a new setting - we already have different colors for the different days, and color-ratcheting is just adjusting those already existing settings to your current situation.