I really like the colouring, but I have to concur that the style is out of place. This is a bleak world so having these occasional super saturated panels feels jarring after just under thirty monochrome chapters. Might work better if it was fully coloured or if this gimmick was present since the start, though, regardless, I would go for a very dark and muted palette personally.
Thanks for also uploading the black and white versions, I will stick with those.