Season the pork all over with the salt, pepper, smoked paprika, and garlic granules.
Set the Instant Pot to sauté. Add the olive oil and brown the pork in batches until properly golden all over. Lift the pork out and set it aside.
Add the sliced onions straight into the pot with a pinch of salt. Cook for 5–6 minutes until they soften and start to colour, scraping up the sticky bits from the bottom. Add the garlic and cook for 30 seconds.
Pour in the beer and let it bubble for a couple of minutes to cook off the alcohol. Add the stock, Worcestershire sauce, and mustard, then stir well.
Return the pork to the pot, nestling it into the liquid. Lock the lid, set to high pressure, and cook for 75 minutes. Let it naturally release for 15 minutes, then vent the rest.
Lift the pork out into a tray and shred it with two forks.
Set the pot back to sauté and simmer the liquid for 10–15 minutes until it reduces into a rich, glossy gravy. Taste and adjust the seasoning.
Stir the shredded pork back through the gravy until it’s properly coated.