I checked, and The Witcher 3 runs in 720p on Switch; 540p is the resolution in portable mode. You also forgot to mention the common framerate drops of the PS4 version to 20 fps.
You didn't address battery life either.
Poor reasearch on your part then because it runs UP TO 720p with 540p being the lowest number in docked mode and it's running at sub 720p a lot of the time.
Portable mode is 440p up to 540p.
On the other hand PS4 is always 1080p which is 4 times 540p and it runs on mix of medium and high details while Switch is on the lowest preset.
And I did adress battery life. Ampere 50 series GPU will provide similar battery life to regular Switch.