Preheat an outdoor grill for medium-high heat and lightly oil the grate.
Mix ground beef, feta cheese, minced onion, red bell pepper, mint, parsley, garlic powder, onion powder, seasoned salt, and black pepper together in a large bowl until evenly mixed; shape into 6 patties.
Cook the burgers until they are beginning to firm, and are hot and slightly pink in the center, 4 to 5 minutes per side. An instant-read thermometer inserted into the center should read 140 degrees F (60 degrees C).
