Turn on the Instant Pot to Saute and wait until the display says "Hot." Add 2 tablespoons olive oil.
Add the diced sweet onion and cook, stirring occasionally, until softened about 3–4 minutes.
Add the minced garlic and cook, stirring, for about 30 seconds.
Add the 1 1/2 lbs ground beef. Break it up with a wooden spoon and cook until no longer pink and browned, about 5–7 minutes.
Stir in 2 tablespoons tomato paste until combined with the beef.
Add the 1 (15 oz) can fire-roasted tomatoes (with juices), 1/8 teaspoon red pepper flakes, 1 tablespoon sweet or smoked paprika, 1/2 teaspoon cumin, 1 teaspoon oregano, the roughly chopped green cabbage (core removed), and 2 cups beef broth. Season with salt and pepper to taste. Stir well, scraping any browned bits from the bottom.
Close and lock the lid. Set the valve to Sealing and select Pressure Cook (High) for 10 minutes.
When the cook time ends, let the pot sit undisturbed for a 5-minute natural pressure release (NPR). After 5 minutes, carefully turn the valve to Venting to release any remaining pressure.
When the float valve drops, open the lid away from your face, stir the stew, taste and adjust salt and pepper if needed, then serve.