First, Tent-H, that sheet pan burger looks amazing. What are you looking at? 135, 155 internal?
My take(s) on the best patty. I love me a good smashed burger. And since they are cooked in only 60 seconds, and on a flat top, you could probably get away with 80/20 or 85/15 since there isn't enough time for the fat to cook out. I make them into very loosely packed 2 ounce balls. Place two on the grill two inches apart on a screaming hot griddle. Smash the super flat. Flip after 60ish seconds, place cheese (American melts the best) on one patty. Top with the other patty and immediately put on buns. Buns need to be toasted with the topping already on them. You don't have enough time to do it while the burgers are cooking.
YouTube "Kenji ultra smashed burger"
Tradition method. From a bunch of different youtube videos they all say you really need to grind your own meat. Wish I had one. You can choose what ever cuts you like for the flavor profile. The important thing is the grinding. When it comes out, lay all of the strands into long rows on top of plastic wrap. LOOSELY. Build it up to a log about 2.5-3.5 inches round. Wrap in the plastic to finish the forming process. Let it chill for a while in the fridge to cool back down. Then slice the rolled log in to desired thicknesses. This method will produce a super tender patty. It is like slicing steak and brisket against the grain for tenderness since the beef strands all run the same direction.