Season short ribs liberally with salt and pepper on all sides.
Set Instant Pot to Saute setting and add a teaspoon of olive oil. Allow it to get hot before adding ribs. Brown the short ribs on all sides, about 2 minutes per side. You will likely need to cook them in batches and then set aside.

While the short ribs are browning, mix together gochujang paste, soy sauce, honey, garlic, ginger, rice vinegar, and sesame seed oil in a medium-sized bowl and set aside. Leave a ¼ cup of the sauce mixture aside for after it is done cooking.

Pour beef broth into the Instant Pot and scrape up any caramelized pieces left from the beef cooking. Place the short ribs in the broth. Pour all but a ¼ cup of the sauce mixture over the short ribs.
Place the lid on the Instant Pot with the vent closed, set to the Meat/Stew setting, adjust to 'more' (or high.)

For bone-in: set the timer for 45 minutes. After it is done cooking, allow it to naturally release for 10 minutes and then open the vent.

For boneless: set the timer for 40 minutes with a 10 minute natural release.

While it cooks, add sesame seeds to a shallow dish and cook until lightly browned, then set aside.

Remove the short ribs from the Instant Pot and pour the remaining ¼ cup of sauce over them. Top with toasted sesame seeds and sliced green onions.