I'm looking to upgrade my Nikon D7000. My choices are Nikon D500, D750, or D810. I'm not heavily invested into either DX or FX lenses

I'm looking to upgrade my Nikon D7000. My choices are Nikon D500, D750, or D810. I'm not heavily invested into either DX or FX lenses

What's wrong with your D7000 that you need a new camera?

If you'd truly outgrown your current camera (I used an all-mechanical Pentax until I went digital) you'd know which camera you'd want.

If you need the reach of a DX camera and shoot sports, the D500 is the best choice.

Of the full frame (FX) cameras, the D810 is probably the best choice.

Here are two images shot using the D500 and D800e (the precursor to the D810)

If you can afford the D810, go for that one. It's 2 classes higher than the D7000 and is full-frame.