The manufacturer has no control over what stats YouTube decides to show: viewport is not the same as your panel resolution, it's just the dimensions of the area in which the YouTube video is playing. You can check this for yourself on your computer - open a YouTube video without putting it into full screen, and you'll see that the viewport stat becomes much smaller. As for the TV, if you install one of those system info apps that give you details about the hardware, they'll likely report your display resolution as 4K. YouTube shows viewport in the "Stats for nerds" because that's usually what's relevant to the nerds that are meant to be looking at them.the straightforward method is to show correct display resolution as advertised and promised by the Manufacturer on the stats