Heat a large pot or Dutch oven over medium heat. Add the bacon and cook, stirring occasionally, until just crispy, 4 to 6 minutes. Using a slotted spoon, transfer the cooked bacon to a plate lined with paper towels and set aside, reserving the bacon fat in the pot.
Add the onion, garlic, salt, pepper, and sausage to the pot and cook, breaking up the meat with a wooden spoon, until cooked through and no longer pink, 4 to 5 minutes.
Add the arrowroot flour and stir until well incorporated into the meat mixture. While stirring, slowly pour in the chicken broth. Bring the soup to a boil, reduce the heat to a simmer, and add the Italian seasoning, kale, and potatoes. Cover and cook until the potatoes are tender, 10 to 15 minutes.
Uncover and stir in the creamer and nutritional yeast. Simmer for 5 minutes to let the flavors meld with the creamer. Stir in the lemon juice.
Serve in bowls topped with the cooked bacon bits and garnish with parsley, if desired.