Press the Sauté button and add beef, pork, and onion to Instant Pot. Brown meat until no pink remains. While meat is browning, prepare zucchini and filling.
Place zucchini slices in single layer between paper towels and set aside.
In medium bowl, mix ricotta, Parmesan, half of mozzarella, and seasonings. Set aside.
When meat is completely cooked, spoon into a separate medium bowl and prepare to assemble lasagna. Place layer of zucchini strips on bottom of 7 inch springform pan or cake pan. Spoon 1⁄3 of meat onto strips and spread evenly. Spoon 1/2 of cheese mixture and tomato sauce onto meat layer.
Complete next layer of zucchini, meat, cheese, and tomato sauce. For third layer, top meat with remaining mozzarella. Cover with foil.
Pour water into Instant Pot and place steam rack in bottom. Place covered pan onto steam rack and click lid closed. Press the Manual button and adjust time for 5 minutes. When timer beeps, quick-release the pressure. Serve warm with salad and high-fat dressing.