That’s basically what I do right now except I do have a domain and my ISP doesn’t restrict inbound ports like 443 so it works fine.
Just trying to sort out if I want the headache of a VPS if I don’t need it (costs, maintenance, point of failure, etc).
That doesn’t make a lot of sense. 3840x2160 is cleanly divisible by 1920x1080. You should just have pixel doubling happening. Check that you don’t have some sort of scaling turned on in the TV.
It wont magically look high res, it’ll be 1080p, but there shouldn’t be any blurryness, just the blockiness of 1080p on a large display.