Using the Saute option of your Instant Pot, heat the oil and butter.
First add celery, carrots and onions; cook a few minutes until tender.
Mix in the flour and stir to cook for 1-2 minutes.
Add the broth, milk and tomato juice to the pot and stir.
Finally add the crushed tomatoes, thyme, basil and bay leaves.
After stirring, cover the Instant Pot and switch to Pressure Cooker, cooking for 22 minutes.
Do a quick or natural release of pressure before opening the pot.
Remove the herbs and puree the soup with a hand or immersion blender until it's smooth.
Finish off with cheese, salt and pepper to taste.