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?
I would avoid anything built into the TV.
I would not connect the TV to the internet and use a external media player. Either a Nvidia shield or an Apple TV is your best bet.
You can also try building a media player yourself using a small computer.
Note - The self made media player will be more limited in terms of apps available, unfortunately, as well as streaming quality from some of the streaming services.
We need this info added to an FAQ. This question comes up frequently.