Slice mushrooms and radishes in half, and quarter onions and set aside.
Place 1 tablespoon of olive oil into Instant pot liner, and press SAUTÉ button. Allow to heat, and add in chopped veggies (mushrooms, onions, and radishes). Caramelize the veggies for color. Once caramelized, remove and set aside.
Add remaining olive oil. While heating, add salt and pepper to both sides of the roast. Add sliced garlic and then the roast. We want to sear both sides of the roast, which will take about 3-4 minutes on each side.
Once done, remove roast and set to side, add in beef broth and Worcestershire sauce. With a wooden spoon, scrape bottom of liner to remove any tidbits that might have gotten stuck in the searing process. This will ensure that you don't receive a "BURN" notice on your Instant Pot screen.
Add roast back to Instant Pot and top with butter. Close and lock lid in place, and seal vent to close position. Set timer for 45 minutes. Allow to NPR (naturally depressurize). Do not quick release the pressure.
Remove roast, and set to side. Add veggies back to Instant Pot. Close and lock lid in place, and seal vent to close position. Set timer for 1 minute. Quick release pressure once done. Your veggies will be fork tender.
Be sure to serve with a bit of the jus from the pot over your roast and veggies. So Good!