>>4338708I have a sony a6400 + a Tamron 18-300mm which I use for wildlife and occasional concert photography. I've used a few Nikons too.
I love my old DSLR, but the A6400 is great. A few basic points to answer your questions:
> Sony = shitI hate how tiny and unergonomic they are compared to more grab-able Nikons, but otherwise this is cope. The colour is a **bit** funky when it comes to skin but for nature it's fine; also learn to edit
> AFSony wins, just know how to use different AF zones. I assign the custom button to the AF zone setting so I can quickly go from multiple AF points (moving stuff) to single point (stationary animal shots)
> WildlifeA6400 has animal face detection BUT it only works on animals with noses. I've never gotten it to work on birds
>VideoThe Nikon Z50 and sony are basically identical here
Sony wins for me cause it has the most lenses. Especially considering that for video, it is has been so useful to have in-lens optical stabilization which is common in Sony and Tamron E-mount lenses
The one downside is I sometime get eye-strain using the EVF as opposed to the OVF of my old Nikon D5500
