To the Instant Pot still set on high for SAUTE, add the garlic and beer. Using a wooden spatula or spoon, scrape all the little seared bits and yum yums from the bottom of the pot.
Add back the roast. Add the mushrooms, minced onion, Worcestershire sauce, and tomatoes.
Put on the Instant Pot lid and secure with the pressure release valve set to SEALING.
Set Instant Pot to cook MEAT/STEW, pressure level HIGH, for 60 minutes.
Once cycle is complete, allow to IP vent naturally (meaning, don't touch it) for 10 minutes.
Release the remaining pressure (use a dish towel to protect your hand because some steam will still come out) by switching the pressure release valve to VENTING. Open pot.