The Michelin Star way is 1:1 butter to potato ratio (yes, so 1 pound of butter for every pound of potatoes) and a tiny bit of salt lol. You just run the mash potatoes through a fine mesh until it becomes a super smooth paste.
Restaurant food tastes good because we make it the unhealthy way, and we have commercial grade burners. To quote Beavis and/ or Butthead: "FIRE! hu hu YEAH! FIRE!"
That's why high end star restaurants serve smaller portions. 1) cuz it's usually a lot of ingredients but also 2) there's a psychological aspect where you appreciate the food more because there's less of it.