Start the Instant Pot on "Saute" mode and let it heat up. Wait until the screen says "Hot" and then add the olive oil, onion, garlic, celery, thyme and dill, salt and pepper.
Saute for about 3-4 minutes, until the onions are soft and become translucent. Alternatively, you can skip the saute step to save even more time and simply add all the ingredients together.
Add the zucchini and stir everything together well.
Add the vegetable stock.
Place the lid on the Instant Pot and seal the lid. Place the release valve on "sealing".
Cook for 6 minutes on "Pressure Cook".
When the Pressure Cook time is finished, carefully turn the release valve to "venting" using a long pair of tongs or another long kitchen tool so you don't burn your hand, arm or face. It's a good idea to do this under an exhaust fan in your kitchen, if you have one.
When the pressure has released, open the lid, add the cream (or coconut milk) and blend with an immersion blender or in a standard blender in batches.
Serve while hot with a drizzle of extra cream (optional).