Cut rib racks into slabs of about 3 ribs each. Place in a large bowl, season lightly with salt, and set aside.
In a small bowl or measuring cup, whisk together the orange juice, soy sauce, fish sauce, five-spice powder, sambal oelek, and sugar. Set aside.
Select Sauté on the Instant Pot® and heat the oil. Cook the shallots, stirring occasionally, until soft and slightly browned, about 4 minutes. Add the garlic and ginger and cook until fragrant, about 1 minute. Add the juice mixture and bring to a simmer. Press the Cancel buttonto reset the program.
Pour the five-spice sauce over the ribs and let sit for 5 minutes. Stack the ribs upright in the pot and pour the sauce over the ribs. Lock the lid in place and turn the valve to Sealing. Press the Pressure Cook button and set the cook time for 25 minutes at high pressure.
Line a rimmed baking sheet with aluminum foil.
Let the steam release naturally. Carefully remove the lid and use tongs to transfer the ribs to the prepared baking sheet. Preheat the broiler.
Select Sauté on the Instant Pot® and simmer the sauce until thickened, 10–12 minutes. Brush the top side of the ribs with the sauce, place in the broiler, and broil for 3 minutes. Carefully remove the baking sheet from the broiler. Using tongs, turn the ribs over and brush them with the remaining sauce. Return the ribs to the broiler and broil for 3 minutes.