The front-facing camera of current models of iPad Pro have a higher pixel count than many other iPad models - however, the ultra-wide camera lens can reduce the effective resolution…
The ultra wide front camera features Centre Stage, allowing the iPad to mimic pan and zoom in software - this feature being designed to keep a user centred within the field of view; however, when using Centre Stage, the digital zoom and crop inevitably causes some degradation in image quality, particularly in low-light conditions. Disabling the Centre Stage feature simply provides an ultra-wide camera field without cropping - but will not improve the effective resolution of the camera’s cropped image.
You can find more information about Centre Stage here:
Use Center Stage on your iPad or Studio Display - Apple Support
iPad specifications for all models of iPad can be compared here:
iPad - Compare Models - Apple