Polygon Count Targets (Reddit)

Ultimately determined by the hardware minus however much overhead is added by the render passes you will be using.

6-11 million triangles is somewhere around the upper limit (generously) for the entire rendering.

Use at most one draw call per asset (2 if desperate.)

15-30k triangles for a main player character ("hero asset.")

Assets near the camera or for hero units need priority quality; distant things much less.