For that sort of scene I wouldn't go above 2048 for texture size, my bucket would be set for 32, displacement ticked if using, raytrace bounce at 3, Minumum shading rate at 0.5, Pixel samples at 5, Post filter at 1 and box!  Shadows and raytracing ticked.

That would be my settings for that type of scene!

Injustice will be avenged.
Cofiwch Dryweryn.