Step 1: Cook the bacon in a large skillet over medium-high heat until crispy. Remove bacon with a slotted spoon, reserving 2 tablespoons of bacon fat in the skillet. Crumble the bacon once cooled and set aside.
Step 2: Add the diced onion to the reserved bacon fat in the skillet. Sauté until softened, about 5-7 minutes. Add the minced garlic and cook for another minute until fragrant. Transfer the onion and garlic to the slow cooker.
Step 3: Add the diced potatoes, chicken broth, and ranch seasoning mix to the slow cooker with the onion and garlic. Stir everything together gently.
Step 4: Cover and cook on low for 6-8 hours or on high for 3-4 hours, or until the potatoes are very tender.
Step 5: Once potatoes are tender, use a potato masher to mash about half of the potatoes directly in the slow cooker to create a creamier base, leaving some chunks for texture. (Alternatively, you can remove 2-3 cups of the soup, blend until smooth, and return to the slow cooker).
Step 6: Stir in the softened cream cheese until fully melted and smooth. Then, add the sour cream and heavy cream, stirring until well combined.
Step 7: Add 1½ cups of the shredded cheddar cheese and about two-thirds of the crumbled bacon to the soup. Stir until the cheese is melted. Season with salt and pepper to taste, adding more ranch seasoning if desired.
Step 8: Ladle the hot soup into bowls. Garnish each serving with the remaining shredded cheddar cheese, crumbled bacon, and fresh sliced green onions. Serve immediately and enjoy!