I always wondered if I could install a private OS on a smart TV but never found one.
I like Android TVs because I can install f-droid apps on them. Like Cloudstream. I tried to debloat my TV by connecting my laptop to it and running the adb command to remove any bad apps I noticed, but even that's not perfect.
I wanna become an android developer someday and I might look into developing privacy apps focused on Android TVs.
Edit: I removed google play and it's services, so spyware shouldn't be getting updates on my TV and I got it a few years ago now, I think it's ok for privacy right now.
I use Vanadium and sometimes DDG or Tor. Mulls a good, hardcore browser as well.
And for vanadium, I use an ad blocking DNS, which is https://dns.adguard.com/dns-query
Isn't perfect but it blocks some ads