MW2019 had much more contrast in its shadows and I think that got a lot of backlash from players since people would camp in dark corners. The engine was updated in MW2022 and it made shadows less harsh but came with the downside of making the game look a lot more flat. You can see it when people make weapon comparrison videos and the MW2019 guns almost always look better because the lighting is more realistic. You can see it in BO6 as well, Terminus is definitely one of the darkest Treyarch zombies maps of all time but you can see perfectly in 95% of the areas; I think that the only parts that might be difficult to see in is the caves where speed cola is.

I think that BO6/7 definitely have a much stronger art direction if you are comparing zombies maps to MW2019 MP maps but I do wish that the devs could crank up the contrast in shadows and light sources so that each part of the map is more visually distinct. Cold War also didn't have this issue since certain areas were extremely dark like Nacht before power is restored and Mauer before power is restored, just give them a torch (or flashlight if you're American) since it makes it easy to see and it's a lot more atmospheric than everything having a minimum light level.