My "smart" Vizio TV and LG projectors just go directly to the last active input (in my case a Google TV). I never even remember they have their own built-in smart OSes because I never see them.
However, these days, most of the streaming sticks have their own shitty recommendations and ads anyway, so unless you're doing a self-hosted Plex box or something, expect ads. And then of course there are the actual streaming service ads.
The Apple TV menu only shows preview cards for apps in the top row. Most apps show what you're currently watching, but other apps (Prime Video, ATV+, Twitch) will show promos instead. Best to move these apps to the right end of the top row, or down into the 2nd or 3rd row.
However, these days, most of the streaming sticks have their own shitty recommendations and ads anyway, so unless you're doing a self-hosted Plex box or something, expect ads. And then of course there are the actual streaming service ads.