Cut the chuck roast into 1.5 to 2-inch pieces (not small dice). Pat them very dry with paper towels. Season generously with salt and pepper immediately before cooking to prevent moisture loss.

Set Instant Pot to Sauté (High). Add oil. Once shimmering/smoking, sear beef in batches (don't crowd). Get a dark brown crust. Remove meat to a plate.

Add the large onion, carrot, and celery wedges to the empty pot. Cook for 3-5 minutes, scraping the bottom with a flat-edged wooden spoon until they start to brown.

Add the minced garlic, tomato paste, and oregano. Stir constantly for 30 seconds until fragrant.

Pour in the red wine and beef broth. Scrape the bottom of the pot vigorously to remove all browned bits (fond).

Return the beef (and any plate juices) to the pot. Nestle the rosemary sprig on top. The liquid should come about halfway up the meat.

Lock the lid. Set to Pressure Cook (Manual) on High for 35 minutes.

When the timer beeps, place a large Ziploc bag filled with ice directly onto the metal part of the lid (avoiding the valve). The pin should drop in about 5-7 minutes.

Allow a Natural Release for 15-20 minutes.

Use a slotted spoon to transfer the meat and veggies to a serving bowl. Skim the fat off the liquid (using a ladle or fat separator).

Stir the Red Wine Vinegar into the hot sauce. Taste for salt.

Pour the sauce over the meat and vegetables. Garnish with fresh parsley.