I don't cook burgers very often so I'm not really an expert on them, but the last set I did this summer turned out amazing.
I should have wrote down the blend, but basically it was like 80/20 ground beef, melted butter, a squeeze of ketchup, shredded/pulpy onions and panko bread crumbs. I might have added an egg but I don't recall. So yea, it was kinda like a meatball, but it didn't taste like one. The onions and the breadcrumbs basically just helped to add and retain moisture. The panko absorbs moisture and by the time they're cooked and you bite into it, you can't even tell there's breadcrumbs at all.
Anyway, I made some pretty thick patties and I cooked them differently then I've typically done in the past. For most meats now I've essentially become a reverse sear for all. So I reverse seared these burgers. I stuck my therm in one, got Audrey to 225 and brought the burgers up to 110 before taking them off and getting the fire screaming hot. Put them on for maybe 2-3 mins a side to get a nice sear on em. put them on the indirect side with some cheese, closed the lid and boom. A minute later some amazing burgers. They were cooked perfect medium rare with a thick band of red to the edges.
One of the best things I've cooked on the grill.
So yeah, if you have the time, space and a good therm, try reverse searing burgers next time