I know it’s not a popular option around here and expensive but I absolutely love my Apple TV.
Besides the set up plug for Apple TV+ I never get any ads from the OS outside of the specific apps. Yeah, you go into Amazon or something you get their ads all over but not sure you can do anything about that. Even without a pinhole it’s a much better experience compared to my TV (when I allowed it online) or a friend’s Roku with piholes.
Overall though it’s an unobtrusive OS, has apps that are updated well, supports high quality output (4K/atmos etc.). You just have to pay up front for it, but of all the Apple stuff it’s the best bang for the buck. I love to tinker with my tech but for TV, me (and especially) the family need something that just works nicely without needing to fiddle with it.