You'll find that the ATV is way more smooth and responsive in use than on any Samsung TV. IMHO almost all "smart systems" on current TV's is slow and sluggish. Samsung doesn't excel in this deparment. They can make good electronics, but software integration is just crap.
On the ATV 4K (2021) you can enable the Audio Return Channel option. According to the
AppleTV Support page, that should make it possible to play audio from the TV (Xbox on another input) via the ATV 4K to the HomePod minis. Not sure if there's a significant delay in this use. It probably depends on what the TV itself supports on all of its HDMI connectors.
Our benefit of getting the AppleTV 4K, less cables, less devices and portability. It replaced a big cable box and a DVD player. It is so small that it can be mounted on the back of the screen too.