Place the roast, red bell pepper, Zesty Italian Seasoning Mix, Butter and Pepperoncini Peppers (including juice) and the beef broth in the instant pot.
Seal the instant pot by placing the valve on the top to the seal position.
Cook on high pressure for 70 minutes with a 15 minute natural and then release the remaining pressure on the instant pot.
Shred the beef and mix it into the juices in the instant pot.
Slice the hoagie rolls and place them face up on a baking sheet. Broil the rolls on high for 3-4 until the bread is browned slight. Place the meat mixture on the bottom of the rolls, then layer on the sliced cheese, then broil for 1-2 minutes until the cheese is melted. Place the top of the roll on top.