First make the stock. Pound the garlic, coriander stems/roots, and white peppercorns into a paste using a pestle and mortar. Heat your instant pot on saute to low. Add the oil and fry the paste for a few minutes, until you can no longer smell raw garlic. Scoop the paste out into a bowl.
Add the palm sugar and cook for another couple of minutes, stirring constantly, until it turns a few shades darker. Don’t let it burn.
Add water and all remaining soup ingredients, including the garlic/coriander root/white peppercorn paste. Turn the instant pot to slow cook on low heat (sealed), pop the lid on, and cook for 8-10 hours.
When the soup is finished, use a fine mesh strainer to remove the solids. Set the shiitakes aside to cool. When cool, chop and return to soup. Discard everything else.
Add the faux meats (approximate handful per person) and pressure cook on high for 1 minute. Let the pressure release naturally.