I think the shape kinda fucks it no matter what. But if I had to do it, maybe id try shredding a soft cheese like mozzarella or muenster, or maybe even American or cheddar, then grill/dice peppers and mold the cheese / pepper mixture into a pyramid shape. Then wrap the outside 4 sides with thin layers of beef like a smash burger size. So they cook through, and you just get a goey mess of peppers/cheese melting and pulling away when you bite into it.

The top being pointed still sucks though