Turn on Instant pot on sauté normal mode. Heat oil. Now add garlic, onion, and celery. Saute for a minute.
Now add carrots, potatoes, wild rice, vegetable broth, salt, and poultry seasoning. Stir the soup.
Put the lid, vent valve in sealing position. Set to manual/pressure cook and set timer to 45 minutes under high pressure. Once done, switch off and give a quick release.
In a pan, heat butter. Add all-purpose flour, cook for 2 minutes. Now, add half and half milk and stir. Cook for 2 minutes. Switch off the flame.
Now, open the instant pot lid, add spinach, basil, and prepared roux in a soup. Mix well. Cover the pot and let the soup rest for 5 minutes to mingle all the flavors.