so with premium do you get a lot more 1080 material served up rather than 720 ?
recently got a new laptop and at least for both youtube(Ublocko) and skygo those produce a better quality picture on the panasonic/4k tv if you let it do the upscaling,
and tell the laptop that the external/hdmi tv is only 720,
maybe native youtube app on the tv would produce a better picture, albeit with adds.
(I need to survey some of the content I see regularly with get-yt , and see if they have 1080 streams available for premium users, even though they don't have 4K)