Most bars and restaurants do NOT Grill their burgers, they cook them on a Flat Top at relatively high heat.
They make a ball of beef, not a patty, they place the raw ball of beef directly on the Flat Top and smash it down to their desired thickness, add salt and pepper and leave it sit until the bottom is nice and crispy, it’s called, THE MAILLARD REACTION.
As soon as they have created that crust, the burger is flipped and the cheese is applied if desired. The burger is left to continue cooking to desired doneness.
Flat Tops are becoming very popular , Blackstone, PitBoss, Camp Chef , etc all make them for home use. If you don’t have a flat top you can accomplish the same by cooking your “smash burger” in a heavy cast iron pan.