Put 3 ½ cups of the broth along with all of the other ingredients (except the Za'atar) in the Instant Pot. For the honey, use only 1 teaspoon, but keep the rest close by. Close and set the sealing vent to the center position.
Set the time for 15 minutes (manual, 15, manual). Allow to come to pressure and cook.
When time is up, let stand for 10 minutes or longer before releasing.
Throw a towel over the Instant Pot and release the sealing vent. Allow steam to escape. Uncover pot and taste test. Add salt, starting with ¼ teaspoon, and more honey (and harissa) to taste.
Sprinkle individual servings with Za'atar for even more flavor.
If you need to you can add a little more broth, otherwise, save the remaining broth and use it to dilute any leftover soup. It's good on Day 2, but the vegetables absorb the liquid.