Place bacon in a large skillet and cook over medium-high heat, turning occasionally, until evenly browned and crispy, about 10 minutes. Reserve drippings in the skillet, and drain bacon slices on paper towels.

Combine milk and cream cheese in a blender and process.

Combine cream of potato soup, cream of mushroom soup, corn, and cream cheese mixture in a large pot over low heat. Bring to a simmer, about 5 minutes. Add cooked bacon.

Heat skillet with bacon drippings over medium heat. Add halibut, mushrooms, green onions, and garlic. Cook and stir until tender, 5 to 7 minutes. Transfer contents of skillet to the pot with the soup.

Season soup with cayenne pepper and cook until heated through, about 5 minutes more.