If you're running in DX crop all the time, consider a D500. The sensor's smaller, sure, but I don't have noise problems at ISO 2000, and the blazing fast shutter has caught a lot of jump shots I'd probably otherwise have missed. I do use a D850 for macro work, but I wouldn't replace the D500 for wildlife. (Or the 200-500, which is amazing, even if it does make people think I must be a pro and lead to being annoyed with questions when I'm just trying to take pictures of birds.)
edit: Doesn't have the D850's focus peaking in live view, though, as far as I know. I never use it for that, so better off checking the manual.
All fair points. I could only afford one camera body to replace my ageing D3s, and I do use FX for other applications, so the D850 was my choice.
Focus peaking for video is amazing: you can move the focus from the foreground to the horizon and literally see a wave of red 'in-focus' tracking up the frame. For video, I'm a complete convert to live-view.
[Edit]. With practice, focus peaking makes it possible to track a moving animal (e.g. a squirrel approaching you across the ground) using manual focusing, without any of the dreaded auto-focus-hunting that can completely wreck a clip. You just have to learn instinctively which way to rotate the lens to move the plane of focus closer or further away.
A video tripod head also helps, so that you can pan and elevate the camera with one hand while focusing with the other. With a normal tripod head, that has separate locks for panning and elevating, simultaneously moving and focusing requires three hands.
edit: Doesn't have the D850's focus peaking in live view, though, as far as I know. I never use it for that, so better off checking the manual.