Hi sir, most of todays smart tvs comes with Google TV OS and Airplay feature too. Apple TV is like a set top box as you know, it delivers good picture quality supporting the 4K HDR Content and Dolby atmos audio based on the setup we have. If the TV, Audio system supports it then you may go with apple tv.
When the TV dont have airplay we can use apple tv to wireless stream our iPhone, iPad and Mac.
For all other content regular streaming works TV built in google tv OS itself sufficient.
Apple TV can be considered only if you are into the apple eco system and prefer the apps, games and easy wireless sharing between your apple products.
Apple TV+ and other streaming contents are great too, with apple tv.
Decide based on how you will be using the TV + Audio setup sir.