Batch rendering average polycount

After reading this very helpful article by Andrew Maximov, I have a question about how Unreal engine deals with my imported meshes. Basically he says there is a sort of sweet spot for your polycount per objectm whereby you should try to not waste polys but also try to not have them under a certain amount either, as it’s wasted GPU rendering time.

I gather each engine is different, and that this is a hard question to answer as every game is different. Lets say it’s for an FPS console game, and we want to know what the polycount average for should be for objects in the environment. Does anyone have even the slightest idea of what that might be?

Also I did some searching and I’m aware this question gets asked almost daily, but my question is relating specifically to the batch rendering average polycount, and not just picking a number for your game. That’s assuming it works like this and I’m not totally misunderstanding it.