In a shallow bowl combine the garlic powder, onion powder, paprika, sea salt, and black pepper.
Season the sliced round steak on both sides with the seasoning mixture.
Press sauté on the Instant Pot, and when it reads Hot, add the oil.
Once the oil is simmering, brown the steak on both sides, then place on a plate and cover with foil. Work in batches.
Add the diced onion to the Instant Pot and cook for 1 min. Add the sliced mushrooms and celery, and cook just until slightly soft, stirring occasionally for 2-3 mins.
Add 1/3 of the beef broth. Using a wooden spoon scrape the bottom of the pot to deglaze it.
Press cancel to turn off the sauté mode, and add the round steak back to the pot. Add the remaining beef broth and top with the crushed tomatoes, at this point do NOT stir the tomatoes into the broth.
Cover with the lid, lock it, turn the valve to the sealing position, and pressure cook for 20 minutes. Once cooked, allow for a 10 minute natural pressure release, then do a quick pressure release to remove remaining pressure.
Open the lid, remove steak and place on a large platter. Cover with foil.
Press sauté and boil the gravy mixture for 10 mins to thicken it and reduce it.
Garnish with chopped parsley and serve Instant Pot Swiss Steak over mashed cauliflower, with the gravy on top.