Resolution is the only factor not the connection type. Think you've gone about your investigation to your problem a bit skewed
With a gpu like a 1060 should really be playing at 1080p otherwise cpu can be a bottleneck.
It's difficult to trust and compare videos to your own pc because there are so many variables to consider. Such as Windows version and associated features like Game Bar or Nvidia Geforce Experience can have an negative effect. Other things that can affect performance as well are too many background running processes, chipset/gpu drivers, power plans, quality settings both in gpu 3d management and game. So unless you know for sure everything is exactly the same software wise, in and around Windows, videos can be...