I am a Nikon shooter as is my wife. We are both in our 70's. Our gear is D500/D800 [me] D7000 [kept in car camera] and my wife's D7100. All our lenses are Nikon from 50mm, 70-200, 200-500 500 pf and 500 f4.
From what I have read and heard the Nikon mirrorless system is way behind Sony.
Is switching to mirrorless now or later going to give me better pictures? Besides being lighter AND having eye detection, will the Sony improve my photos? What exactly should I expect to see if I change? Not sure if my wife is interested changing but I thought maybe just a Sony body and the 200-600 for a start.

I presently have a Nikon D750 and the following Tamron lenses: a Tamron 24-70 F/2.8 G2, a Tamron 70-200 F/2.8 G2, and a Tamron 17-35 F/2.8-4. All will work with the Nikon FTZ Adapter. I’m planning to buy a Nikon Z6 II or a Nikon Z7 II so I can lighten the load for travel. I was thinking about buying the Nikon 24-200 Z lens as a walk around lens. My Tamron 17-35 is light and that will fill out the lower end. Any recommendations on adding a low light Z prime to compliment this setup (35mm, 50mm).

Thanks for your help!

Mike

The early verdict on this camera was that it (like many camera manufactured mirrorless camera's) it had trouble holding and acquiring focus on moving objects.
Nikon is not alone, I have issues with the Sony a9 and a7r4, and the new canon R5 has had issues.
When mirrorless do produce, they really deliver. I save 5 different focusing modes in my a9 and can quickly switch to the one I need for a particular scene.
When I first owned a Sony Mirrorless, the learning curve was steep on learning to quickly getting lock on focus.
Still, my keep rate is not up to my Nikon GROUP AUTO FOCUS focusing system.
My personal advice, get the Z7II if your shooting action shots, other wise the Z7 works great for still photography.
With all of this said, I am getting the hang of it. Below is a recent shot taken with the Sony a9 and Sony 600 mm f4, 1/3200 sec. f4 ISO 500. Red Shoulder Hawk with nesting material.