My parents are getting a new tv, and are asking for recommendation. I think all I can influence is the brand/model (not realistic to propose rpi and more complex systems). I instinctively avoid google/android and lean towards anything else open source, so probably LG WebOS… But I had bad luck searching for more detailed comparisons. Maybe you have experience or opinions?
My advice is never use a smart tv of any kind.
Use a third party device like an apple tv or roku, hell even a bluray player with apps on it.
Then get what ever TV you like and never let it see the internet.
I personally like Visio, but any mid grade display is fine.