I install a lot of new TVs for clients, typically a dozen a week or more, and I have yet to find any SmartTV interface that works as well as the ATV interface. Clean, fast, responsive, uncluttered, and can use the (now) great ATV remote and not the janky zillion-button jobs that come with today's TVs.
And I am here to tell you... some companies pretty much don't care about their SmartTV integration interfaces. And those that do (Samsung, Sony, a few others) seem to have completely onerous Terms of Use including tracking and even ownership of interface and customer data. Completely unacceptable to me and most clients who read the T&C's. And others (I'm looking at you, LG) have good interfaces and unbelievably poor remotes, weird pointer options that are hard to turn off, or invasive Home screens that force you to change inputs or navigate through a mess to get to where you are going - all while the apps "go live" and shout at you while you navigate.
Naw... I like the clean, easy, simple approach of the ATV interface... and in most cases you can use eARC to set up the TV to switch on and off with the ATV remote as well as go to the correct input, output audio to a sound bar or audio system, etc. Just use good HDMI cables that have top-shelf connectivity and pass-thru (try some Monoprice 8k certified cables maybe) and you are all set.