Add the oils to the bowl of your pot, and press the Saute button to turn on. Once the oil's hot (shimmery) add the meat to the pot. Cook just until browned, stirring as needed, but not cooked all the way through.
Stir in the garlic and ginger, then salt & pepper the mixture. Cook, stirring, for 60 seconds. Hit cancel to stop the pot from sauteeing.
Add the soy sauce, onion, mushrooms, and vinegar to the pot. Stir everything to evenly combine.
Add the lid to the pot turning to close, and set the vent valve to the sealed position. Pressure cook on HIGH for 4 minutes.
Carefully turn the valve to quick release the pressure, staying away from the hot steam escaping. Open the lid.
Whisk the cornstarch and water together until the slurry's smooth. Pour it into the pot and stir it in until evenly combined. Let the mixture rest, uncovered, for 2-3 minutes or until slightly thickened.
Add the zucchini to the pot, gently pressing them down into the sauce, close the lid and set the vent valve to seal again. Pressure cook on high for 1 minute.
Carefully perform a quick release of the pent up steam. Once that's done open the lid and stir the mixture- it will still be steamy and very hot.
Check the zucchini and make sure it's done to your liking without being overcooked. If you want it to soften more, just stir again and let the mixture rest for another minute or two.
Serve the steak and vegetables over, or alongside, steamed white rice.