In a large Dutch oven or heavy-bottomed pot, cook the Italian sausage and red pepper flakes over medium-high heat. Stir frequently to break the sausage into crumbles. Continue cooking until the sausage is browned and fully cooked, approximately 10-15 minutes. Transfer the sausage to a bowl and set aside.

Using the same pot, add the bacon pieces and cook over medium heat until crispy, about 8-10 minutes. Remove the bacon with a slotted spoon and set aside, leaving a few tablespoons of drippings in the pot.

Add the diced onion and minced garlic to the reserved bacon drippings. Cook, stirring occasionally, until the onion becomes soft and translucent, approximately 5 minutes.

Pour the chicken broth into the pot, stirring to deglaze and scrape any browned bits from the bottom. Bring the mixture to a boil. Add the sliced potatoes and chopped kale to the pot, reduce the heat to medium, and simmer for 15 minutes or until the potatoes are tender.

Return the cooked sausage to the pot, stirring to combine. Add the heavy whipping cream and mix thoroughly. Allow the soup to simmer for an additional 5 minutes to ensure all ingredients are heated through.

Remove the pot from heat and ladle the soup into bowls. Garnish with crispy bacon bits if desired. Serve immediately with crusty bread or a simple salad on the side.