Set an instant pot to sauté and cook sausage completely. Add in the onion, bell pepper, cremini mushrooms, wild rice, seasoned salt, black pepper, garlic cloves, broccoli, chicken stock, and water. Close the lid and set to pressure cook, non-venting for 25 minutes.
Meanwhile, in a medium saucepan melt the butter and flour together whisking together and cook for 1 minute. While continuing to whisk, slowly pour in the milk until thickened then take off the heat. Add the roux to the finished soup and stir to combine.