I'm considering an 883 to replace a very old Bushnell.
Do you get better results with a phone or dslr?
Do you get better results with either a full or a crop sensor camera?
I have a Nikon D500, also a D750, would it be better to use the crop sensor camera?
I prefer to use an EVF camera because the view at high magnifications can be very dim through a dSLR.
Sensor quality and camera quality is more relevant than size. Most important is matching the camera lens to the eyepiece. A "normal perspective" pancake lens (i.e. with small front element) is a good starting point.