Instant Pot Turkey Breast with Gravy

1 7-pound bone-in turkey breast

3 tablespoons butter softened

1/2 teaspoon paprika

1/4 teaspoon garlic powder

1/2 teaspoon salt

1 1/2 cups chicken broth or water

1 small onion quartered

2 small celery stalks cut in half

2 tablespoons plus 1 teaspoon cornstarch