Why is there no per-app contrast setting for iMessage on macOS?

It's really hard for me to read the forced green bubbles for SMS in iMessage. I'm a little color blind, and this washed out green/white combo is the only real problem I have seeing things easily. I was pleased to see that I could turn on higher contrast per app on my iPhone; I can see it SO much better now! I am also glad it's a 'per app' setting. I don't want to change things that are not problematic. Since you don't allow users to change the colors by design, this is at least something that works for your end users that have been asking about this for years. The bad news is there is no 'per app' setting for MacOS, I don't believe. Why not? I'm updated to the latest version on both iPhone and Mac, and both devices are only a year old, so this has nothing to do with my devices or your software, other than the decision to disallow per app contrast/accessibility changes in MacOS like iPhone. Is this coming? I went from being very happy to being quite disappointed as I use both devices a lot, and my daughters use Android/RCS, so this is very important to my everyday life. Thanks for any info on if MacOS will also change soon?