As far i am aware of no other region other than the US has 4k and Dolby Atmos which is separate to the international app so a a UK subscription with a VPN won’t work.Really, what is the point in releasing it if they have no 4K/HDR/Atmos content? No doubt they will charge the same money for other regions that have it.
You don’t use your Sky ID. You set up a paramount account via the Q box which says the cost is £0 during the set up process. You can then log in to the app on an Apple TV which looks to be a much better option than the Q box from my brief tests.I couldn’t find Paramount plus anywhere on the sky Home Screen I had to do a voice search for it is it no where on the Home Screen. Also as a sky cinema subscriber with Sky Q I will not be charged for this will I. And also if I want to watch this through my Apple TV App can I use my sky Id.