Add beef stew meat to a bowl.
Mix together flour, kosher salt, and black pepper.
Sprinkle flour mixture over the beef and toss to combine. You're not looking to fully cover the beef in flour just enough to help it brown up nicely.
Add your Instant Pot to the saute setting and add in olive oil.
When the oil is hot add in half you beef and cook until browned.
Remove the cooked meat, add in a little extra oil if needed, and brown the second half of the meat.
When all the meat is browned, add it all back to the pot, and pour in the beef stock.
Using a wooden spatula scrape up all the lovely brown bits from the bottom of the Instant Pot.
Turn the heat to the Instant Pot off.
Stir in Worcestershire sauce, potatoes, pumpkin puree, mushrooms, carrots, garlic, and yellow onion.
Stir to combine.
Add the lid of the Instant Pot onto the pot, close it tightly, and make sure the vent is in the "seal" position.
Set to manual, high pressure, 35 minutes.
After the stew has come to pressure and cooked for 35 minutes allow it to natural release for 10 minutes.
After 10 minutes of natural release, release it manually, remove the lid, and stir the stew.
Add in frozen peas and allow them to warm through with the heat of the stew, about 2 minutes.
Taste and season with additional kosher salt and black pepper if needed.