Since you're on a new Mac Pro, I assume all of your software is up-to-date via Apple software update. (There are no separate user downloadable graphics drivers.)
It could be related to your monitor's contrast settings - unless you you see the gray-shaded rectangle in AC 17, 16, etc? You may need to calibrate your monitor to the Mac Pro's graphics cards... System Preferences > Displays > Color tab and Calibrate... so that light grays are not washed out?
It's possible that it is something related to the new graphics cards in the new Mac Pro. Which card(s) are in yours? Then maybe someone else with that model can test.
AC 28 USA and earlier • macOS Sequoia 15.4, MacBook Pro M2 Max 12CPU/30GPU cores, 32GB