"Reach" is a combination of pixels on the target and lens resolution. As Shun pointed out, a DX cropped D780 is only 10 MP; that's nowhere near the 21 MP on target you would get from a D500, D7500, or a DX cropped D850. My suggestion for "reach" would be to upgrade your camera to 21 MP DX (either cropped FX sensor or a DX sensor) and put a Tamron 150-600mm lens on it, and keep the 70-200mm on your D780 (or D850) FX sensor when your subject is too close for 150mm on a DX cropped FX sensor or DX sensor.
Some examples of what I get using these combos:
D850 @ 70mm
D850 @ 190mm
D500 @ 460mm
D500 @ 500mm (cropped)
