Chop the carrots and celery, quarter the onion, and smash the garlic cloves.
Place bones in the Instant Pot, followed by vegetables, garlic, bay leaves, and peppercorns. Pour in apple cider vinegar and add water until ingredients are just covered.
Secure the lid with the valve set to sealing. Cook on Soup/Broth or High Pressure for 2 hours.
Allow pressure to release naturally for 20–30 minutes, then carefully remove the lid.
Strain broth through a fine-mesh strainer or cheesecloth into a large bowl. Discard solids.
Taste and add salt as needed. Let cool completely before storing.