Wrap 3-4 loops of kitchen twine around the thyme and rosemary and tie securely. Set aside.
Add oil to the Instant Pot. Using the display panel select the SAUTÉ function.
When oil gets hot, brown the meat on all sides, 3-4 minutes per side. Meat will not be cooked through. Transfer browned meat to plate and cover loosely with foil.
Add onion to the pot and saute until soft, 3-4 minutes (if it gets too dry, add a bit of broth). Add garlic and cook for 1-2 minutes more.
Add balsamic vinegar to the pot and deglaze by using a wooden spoon to scrape the brown bits from the bottom of the pot.
Add the broth, apple, salt and herb bundle, and stir well. Add the tenderloin back and nestle it in the sauce, turning once to coat.
Secure the lid, making sure the vent is closed.
Using the display panel select the MANUAL function* and adjust the pressure to LOW PRESSURE. Use the +/- keys and program the Instant Pot for 2 minutes.
When the time is up, select CANCEL and let the pressure naturally release for 15 minutes, then quick-release the remaining pressure, if any.
Check the temperature of the meat with a meat thermometer to ensure it is at least 137 degrees. (If it is not, proceed, but see the note below in step 11.) Carefully remove the pork from the pressure cooker to a cutting board and cover loosely with foil.
Using the display panel select the SAUTÉ function. Add honey and butter and stir well to incorporate. Cook, stirring occasionally, for 5 minutes. (If the tenderloin did not reach 137 degrees, add it back to the pot in this step and cook, turning occasionally, until it reaches 137 degrees.)
Remove herb bundle. Scoop out 1/3 cup of the liquid into a small bowl and whisk in the corn starch. Pour mixture back into apple mixture and stir well to thicken.
Slice the tenderloin into medallions and serve with the balsamic-apple mixture. Garnish with additional thyme and pomegranate seeds, if desired.
*The Manual and Pressure Cook buttons are interchangeable.