GraphyTaffy this is the only way.
GrapheneOS is not just Android with a bit of debloating. It is huge work to make it private. And Android phones are based on the FOSS AOSP.
I am not sure about Android TV, but they will likely have a ton of additional proprietary stuff on it, for like everything. The UI etc?
You simply cannot use any random TV privately, if you are not able to build an OS that has the correct drivers (hardware) and features (software) you need.
I use a Chromebook as my "TV". There is no Linux Desktop that works well, apart from Plasma Bigscreen, but not sure.
Depends on your media consumption too. No idea what you do. I am really happy with my TV user account, movie collection, and remote control via KDE Connect.