It’s the principle of the matter to me. Google became the multibillion dollar corporation it is by selling my data, your data, everyones data. To then come around and demand I pay to continue using their service the way I have for over a decade? But also still continue selling our data? Nah, fuck that. When they cut me in a percentage on the data selling business, maybe then I’d consider premium.
Can’t help you with any of the other stuff, but to answer your 4k question: No, you still need your 4k collection for best quality. Upscaled 1080p is still 1080p, it just makes it not look wonky on a 4k display. Any details lost due to the source resolution will still be lost, you can’t create extra detail out of thin air.