Some TCL TVs will refuse to work unless you connect them to a network with access to the home base. Fortunately, my Samsung S95D doesn't (lovely matte OLED screen), and is perfectly usable without a network connection or even setting up the Smart TV features. The only controls I need on it are volume and HDMI input switching. Like you, I use two AppleTV 4Ks as sources, one tied to my US Apple ID, one for the UK one. At some point, I will also connect my Oppo UDP-203 4K Blu-Ray player, but I haven't needed to in the 2 years since I moved to the new house.