I have Note 9 and had heavy night mode redness. It was due to Google Play Book
I would also check if Google Photos or any other photos app has same behavior
If no luck with above two, try clearing cache (or even storage) from App Manager > Gallery to reset the app settings
I never even had Google books on my phone and it was still the problem, I had to go download it from the play store and do the fix. It worked but how did it happen without ever even having the app in the first place?