A:Answer Yes, since the video encoding is happening on the laptop (assuming the laptop is the 2nd PC with OBS / Stream Labs) the 1st pc doesn’t have to do that work.
Essentially the 1st pc doesn’t even know it’s being recorded, so getting this capture card will improve performance on the 1st pc to the point where you don’t even notice any performance drops from recording.
There will be more input lag, and also it will only output 60hz, but other then that you shouldn’t notice a performance drop at all on the 1st pc it should perform like you are playing the game without recording.