Preheat the air fryer and cook the French fries according to package instructions until golden and crisp.

Meanwhile, preheat the oven to 350°F.

Heat a large skillet over medium-high and add the ground beef and diced onion; brown until no pink remains and the onion softens.

Stir in minced garlic and cook for 30–45 seconds until fragrant. Season with garlic powder, onion powder, salt, and pepper.

Drain excess grease from the pan.

Mix in the cream of mushroom soup and cheddar cheese soup until the mixture becomes thick and saucy.

Transfer the beef mixture to a 7x11 casserole dish and spread smooth.

Layer the cooked shoestring fries over the beef in an even layer.

Sprinkle shredded cheddar over the fries.

Bake at 350°F for 10–15 minutes, until the cheese melts and the edges turn lightly golden.

Whisk the mayonnaise, ketchup, mustard, pickle juice, dehydrated onions, and black pepper in a small bowl until smooth.

Drizzle the sauce over the casserole, slice, and serve hot.