Turn the Instant Pot on to the “saute” function and preheat while you prepare the roast.
Dry the roast with paper towel and season one side with salt and pepper.
Add 1 tablespoon of olive or avocado oil to the Instant Pot, then add the roast and sear on one side for 6-8 minutes without moving.
Season the second side with salt and pepper, then flip the roast and sear for a further 6-8 minutes.
Remove the roast from the Instant Pot and set aside on a plate.
Add the bone broth to the Instant Pot and deglaze by scraping the brown bits off the bottom of the pot with a wooden spoon.
Turn off the Instant Pot, then add the au jus gravy mix and ranch seasoning and stir to combine.
Return the roast to the pan, along with the meat juices. Spoon the gravy mix over the meat.
Layer the butter and pepperoncini peppers on top of the meat and add a splash of the pepperoncini juice (if desired).
Put the lid on the Instant Pot and cook on high pressure for 50 minutes.
When the cooking cycle is complete, allow the Instant Pot to complete a natural release for 20 minutes. If after 20 minutes the pot is still pressurized, use quick release to release the remaining pressure.
Remove the roast and pepperoncini peppers from the Instant Pot. Shred the beef with forks and remove the stems and seeds from the peppers.
Finely slice the peppers and mix back through the beef.
If necessary, separate the fat from the remaining liquid, then pour the liquid over the shredded meat.
Serve with your favorite side or in bread rolls as a sandwich.