Soften the cream cheese and combine it with the diced onion, celery, and minced garlic in a bowl.

Sauté the bacon in the Instant Pot until it is browned and crispy. Transfer to a paper towel to drain.

Add the onion, celery, garlic, kosher salt, and black pepper to the pot. Sauté for about 5 minutes.

Stir in the cubed potatoes and the chicken broth. Secure the lid on the Instant Pot and cook on high pressure for 10 minutes.

After cooking, allow the pressure to release naturally for 10 minutes, then perform a quick release.

Turn on the sauté function; whisk in the milk mixed with cornstarch and add the cream cheese. Simmer for about 4 minutes.

Let the soup cool for about 10 minutes before serving. Garnish with bacon, cheese, and scallions.