Place the ribs into a large pot, filled with enough cool water to cover the ribs. Bring the water to a boil over high heat, then immediately turn off the fire. Discard the gunky water, then rinse the ribs until clean. Drain and set aside.
Peel and cut the daikon into large chunks. Set aside. (Note: don't cut the daikon too small as they will "melt" into the soup)
Turn on the sauté function of the Instant Pot and wait until the "hot" indicator is on.
Add neutral oil, swirling until pot is evenly coated with oil, then add the smashed ginger and stir until you can smell its aroma.
Add the parboiled pork ribs and sear until slightly brown, followed by the daikon, water, chicken bouillon powder and sea salt. Stir briefly until ingredients are thoroughly incorporated.
Close the lid to the Instant Pot and ensure that the steam valve is in sealing position, then cancel the sauté function and pressure cook on high for 40 minutes.
After 40 minutes, allow the pressure to naturally release completely, or do a quick release 15-20 minutes upon completion.
Turn on the sauté function once again. When the soup begins to bubble, add watercress, submerging them into the hot soup until they become fully wilted. Allow to boil for about 5 minutes, or until cooked to your liking. (Note: Do not overcook the watercress, as they will turn yellowish in color)
Add white pepper powder and additional salt to taste and top with optional dried goji berries. Enjoy!