Turn the Instant Pot on to SAUTÉ and once it indicates that it's hot, add avocado oil.
Season the short ribs with salt and pepper.
Add the short ribs and sear for 5 minutes per side.
Once the short ribs are browned, remove from the Instant Pot and set aside on a plate.
Add onion and carrots to the pot and cook stirring until the onions are softened, about 5 minutes.
Stir in garlic, tomato paste, and thyme leaves and cook for 1 minute.
Pour in bone broth, balsamic vinegar, and coconut aminos, and let the mixture simmer for 2-3 minutes, while scraping any brown bits on the bottom to deglaze.
Turn off the SAUTÉ function and add the short ribs back in.
Screw on the lid and set the vent to SEALING. Cook on MANUAL at high pressure for 45 minutes.
Once it beeps to a finish, let the pressure release naturally for 10 minutes before releasing the vent.
Open the lid and use a slotted spoon to remove the meat and vegetables from the pot.
OPTIONAL: You can skim off the oil from the top if there's too much for your taste.
Set the Instant Pot to SAUTÉ again.
Whisk together tapioca starch and water to make a slurry, and pour into the the pot. Let this simmer for 1-2 minutes until thickened.
Taste the sauce and add more salt, if needed.
Serve the short ribs with the vegetables, drizzled with the thickened braising liquid. It's delicious over mashed potatoes!