My understanding is that Apple have implemented RCS, which funnily enough, does not even support encryption yet. Google had to roll their own proprietary add-on.
https://www.macrumors.com/2024/09/18/end-to-end-encryption-rcs-messages/
That’s the privacy policy for the AppleTV app. Here’s the specific information on AppleTV device settings:
https://support.apple.com/en-tm/guide/tv/atvb66239fa1/tvos
You can share analytics data with Apple or app developers in order to improve their software. Sharing this data is completely optional
Seriously, buy an AppleTV. It works standalone without the need for other apple products. Has a fast processor, ability to disable telemetry, good track record of software update support etc. and NO.ADS.IN.THE.OPERATING.SYSTEM.
Using an Android box will result in the same issues you’re trying to get away from with SmartTVs.
If you’re technically capable enough you can build your own HTPC, but due to DRM you’re going to run into issues streaming 4K content from streaming services. And PC and Linux HDR and Dolby Vision support is a rabbit hole.
Just buy an LG and use an external media device. LG TVs work perfectly fine with no network connection and you can set them to power on and go straight to the last used HDMI input.
I never see the built-in OS on my LG OLED.