Consider setting the ISO first and then either the aperture OR the speed depending on whether your interested in depth of field or stopping the action. If you choose the aperture you'll get sharp subject with the bokeh you create with the correct aperture, but if you choose speed you can either create a blur with slow shutter speed or freeze the action with a fast shutter speed --- your choice.
Use a ring light for the
best lighting. You are on top of the subject and need light from all around.
Run your FF camera with your chosen lens and put your extender on your crop camera. That way you'll get the advantage your extender was designed for.
Tokina 100mm f/2.8 Macro lens. Sharp and great for portraits as well.
Tokina 16-28 or the Tamron 15-30 both are excellent lenses.
Check out Laura Shoe and Anthony Morganti and Matt Kosklowski, all have great skills in Lightroom, Photoshop and other editing programs.
The Osprey photo --- well done.
Local camera stores in my general area have all disappeared. It's many miles of driving before I can get to one. There was one less than a mile from me - CLOSED. The store where I bought my first Nikon and later my Rollei, is now GONE. Another about 5 miles from me - CLOSED. We need to support the stores we still have so we all benefit. Taxes must be paid whether it's directly charged by a store or we pay a use tax to Uncle.
I have the Tamron 24-70 G2 and love it. Very sharp. You can purchase this lens and use the money you save to take a photo trip to test out that baby. The Tamron would be a great choice.
Sounds like the OP had photoadjustophobia.
I have the Tokina AT-X Pro 100mm f/2.8 D Macro lens and I love it. You can save a bundle due to it's low cost. You don't need more.
IMO, the D850 is the ultimate. For the D850 to be penultimate, you would have to be talking about a better mid frame high res camera.
One vast landscape may reveal several telephoto landscape photo opportunities. You can compose several images in the same vast landscape.