Heat olive oil in a large skillet over medium-high heat for about 1 minute until it shimmers. Add ground beef and cook for 6-8 minutes, breaking it into small crumbles until no pink remains and golden-brown color develops on the edges.

Drain excess fat by tilting the pan and carefully spooning it out. Return beef to heat and add taco seasoning, garlic powder, onion powder, salt, and pepper. Stir constantly for 1 minute to toast the spices until fragrant. Transfer seasoned beef to a bowl and set aside.

Wipe the skillet clean with a paper towel and return it to medium heat. Place one tortilla flat in the pan and sprinkle a quarter of the total cheese on one half of the tortilla only.

Once the cheese begins to melt (about 30 seconds), add half the cooked beef, half the diced onions, and half the bell peppers on top of the cheese. Sprinkle another quarter of your total cheese over the beef mixture.

Fold the empty half of the tortilla over the filled side and press down gently with your spatula. Cook for 2-3 minutes until the bottom is golden brown with crispy spots, then carefully flip and cook another 2-3 minutes on the second side. If necessary, slide it onto a plate and flip with another plate, then slide back into the pan.

Remove from heat and let rest for 1-2 minutes before cutting into 3-4 wedges. Top with half the sour cream, cilantro, and avocado slices. Repeat the process with the remaining ingredients for the second quesadilla.