So in the price range of 500-580 euro it should have 50-55 inches and Prime, Netflix, Joyn have the picture quality, I just don't know my way around
A Samsung TV but then an Apple TV on it. Is the best Smart TV you can get.
Buy a normal FullHD TV or UHD TV.
You then connect a MediaPC or a streaming dongle to which you connect your smartphone and control everything.