Preheat Instant Pot until display says Hot. Add olive oil, onion, garlic and mushrooms and saute for 5 minutes, stirring occasionally. Add thyme, stir and press Cancel.
Add rice, 4 cups of broth and wine. Stir, close the lid, set valve to Sealing and press Pressure Cook or Manual for 3 minutes.
After let pressure come down on its own for 10 minutes, then turn valve to Venting to release remaining pressure. Add remaining 1/2 cups broth, butter and Parmesan cheese. Stir risotto gently and add more broth, if you wish, to reach your favorite consistency.
Garnish with parsley and serve hot immediately.
Notes
Store: Refrigerate leftovers in an airtight container for up to 3 days.
Freeze: Freeze in an airtight container for up to 3 months. Thaw in the fridge overnight or on the counter for 5-6 hours.