I totally get your frustration. The redesign feels off, especially in Siptah. Maybe a private server could help some let you tweak visuals, so you could bring back the old grass vibe.
If I remember the reason they changed the grass was so when players placed down foundations or workbench’s on the grass it would disappear to prevent clipping.that’s when I last noticed the change….. I could be completely wrong tho.
I too have noticed a change in the grass, it appears more brown now. It happened a while ago and it just doesn’t look as good. If you go to the Pagoda of Boundless Lusts, this new grass is too brown for a lush environment like the jungle. I do not know if the graphical performance setting affects this or not, I play in performance mode.