hey, so a few months ago i got a TCL TV with Android TV - because the implementation on that model is very poor, not to mention the weak hardware, I ended up buying a Nvidia shield.
What i want to to now is essentially make the 'smart' TV stupid, just a giant screen, where i can switch between a few different inputs. Is that even possible? if yes how would i go about it?
The TV is a TCL 50EP660
Just do not let it connect to the network during setup.
Maybe disable WIFI/LAN to disable Internet and set it in the Restricted Profile so you can disable some apps.
CEC should let you go from device to device with the individual device remote. There should almost never be need to use the TV OS for anything but maybe changing display settings.
Do a factory reset, one of the first questions it ask is if you want to enable the smart features or not. Haven't tested it.
There are newer firmwares for some TCL tvs that fix the shitty performance and need to be installed manually.
I use v634 in a p8m and it works pretty nice.
I doubt you will be able to totally disable your TV's smart functions, but by turning off the WiFi or disconnecting it from the internet, it should make the smart features useless.