Preheat oven to 375°F. Grease a 9×13 inch baking dish with cooking spray or butter.
Heat olive oil in a large skillet over medium-high heat. Add ground beef and break apart with a wooden spoon. Cook until halfway browned, then add diced onion. Continue cooking until beef is fully browned and onion is softened, about 8-10 minutes.
Add minced garlic during the last minute of cooking. Drain excess grease from the beef mixture.
Season beef with garlic powder, onion powder, smoked paprika, salt, and pepper. Stir to combine.
Arrange half of the sliced potatoes in an even layer on the bottom of the prepared baking dish.
Spoon the seasoned ground beef mixture over the potatoes, spreading evenly.
In a mixing bowl, whisk together cream of mushroom soup, cream of chicken soup, and milk until smooth.
Pour half of the soup mixture over the beef layer. Add remaining potatoes as another even layer, then pour remaining soup mixture over everything.
Sprinkle 1 cup of shredded cheddar cheese over the top. Reserve remaining cheese for later.
Cover the baking dish tightly with aluminum foil. Bake for 45 minutes.
Remove foil and sprinkle remaining 1 cup of cheese over the top. Return to oven uncovered for 15-20 minutes until cheese is melted and bubbly with golden spots.
If using French fried onions, scatter over the top during the last 5 minutes of baking.
Let casserole rest for 10 minutes before serving to allow it to set.