There’s no real hard limit on how many polygons your game can handle. It depends a lot on what happens to the polygons, how many polygons are in view at once, any light/shadow calculations being done.
Instead I would set poly limits for each individual object, maybe something like 4,000 triangles for a player model, and then set limits for each small object relative to how much you think they will be seen by the viewer. You don’t really want to be looking at the overall scene triangle count, since it’s very variable and doesn’t tell you much. Make sure your UVmaps occupy as much of the texture space as possible so you’re not wasting video memory, it may also mean you can downsize some textures.
Also I would consider trying to make a level of detail (LOD) system if your framerate starts to go lower. Make some lower quality versions of each model (they don’t have to be too accurate) and then swap out the higher quality models as the camera gets further and further away from it.