Yeah I’m not a huge fan of the backgrounds, either. They aren’t objectively bad but they always look really washed out. Especially in scenes where it’s dark. I had the same problem with Nemesis. All looks a bit flat and generic.
It's on all series now. The computer has smoothed the whole image, there is no more relief.
At the time, the celluloid offered a good image with a relief (different celluloid placed on top of each other), this brought a relief, a thickness.
Whether it's DBS, Sailor Moon Crystal, or other recent anime, they all have the same problem. All images are smoothed, and the background is anchored with no depth relief.
This is one of the reasons that I am recent anti-anime (I make the effort for SM) but it stops there. I prefer watching with celluloid, there was a lot more life.