Rinse your rice a few times before adding it to the Instant Pot.
Add the turkey carcass to the pot
Add water. I like my congee super thin which requires the 5 cups. If you like your congee thicker, use less.
Close the lid and cook at high pressure for 30 minutes. It will take about 20 minutes for the Instant Pot to preheat before the timer begins and another 30 minutes after the cook time for a Natural Release. In total, you are looking at 1 hour and 30 minutes to make the congee.
You will use a Natural Release vs Quick Release for two reasons. 1) The congee still needs this additional cooking time. 2) If you do a Quick Release, hot steaming liquid will splatter out of the pressure release.
Remove the lid of the Instant Pot. Using tongs, carefully remove the carcass. Some of the meat would've fallen off the bones into the congee. If any meat is still left on the carcass, it would easily fall off and you can add it back to the congee. If you wish to add additional leftover turkey meat, now is the time to add it to the pot.
Turn on the Sauté feature and stir the congee for a few minutes with a wooden spoon. It will thicken up as you mix.
Ladle the congee into 4 bowls. Season with white pepper. If needed, you can add a little soy sauce. Top with optional herbs such as green onions, cilantro, and fried shallots/fried onions.