Yesterday I tested 100 zeds and various shadow settings and did not see that much difference on an RTX 2070. I do have Unity's gfx jobs enabled, which may have some effect on that even though FPS generally seems the same with it enabled. I moved the gfx jobs change into the project, so it will be on in a20.1.
Object quality setting matters more than it used to, since we have more block models, which cause more draw calls.
One of our new programmers is researching trees.
I fixed it today. Fix will be in 20.1.
I don't want canned pathing, if that is what you mean by common. The AI should react dynamically to whatever block combination is presented to them and make a reasonable job getting to you. Bandits, once in, will do the same.