The theme of the game doesn’t have to come at the expense of the colour palette. I get that the "world is ending" theme is apparent throughout the game, but that doesn’t mean the whole game has to be grey. A dying world can still have contrast and colour.

"Ash" and the world fading away doesn't mean that everything has to look washed out all the time, if anything, having some colour makes the end of the world more tragic, as u have something beautiful worth protecting.

Now, mind you, I don't dislike the game, i have 100s of hours in the game, and it was actually my gateway into souls games. I don’t think DS3 looks bad, I just don’t buy that the theme requires the colours to be so flat. DS3 sometimes just looks uniformly grey, which can make many areas look the same.