Dice 6 ounces thick-cut bacon. Place in a large Dutch oven or pot. Cook over medium-high heat, stirring occasionally, until browned and crisp, about 8 minutes. Meanwhile, finely chop 1 medium yellow onion (about 2 cups) and 4 large garlic cloves (about 1 tablespoon). Peel 2 pounds russet potatoes and cut into ¾-inch chunks (about 5 cups).

Turn off the heat. Using a slotted spoon, transfer the bacon to a medium bowl; reserve some of the bacon for garnish if desired. Remove and discard all but 1 tablespoon of the bacon fat from the pot.

Return the pot to medium heat. Remove the casings from 1 pound hot Italian sausage if needed and add the sausage to the pot. Break it up with a wooden spoon into bite-size pieces and cook, stirring occasionally, until cooked through, about 6 minutes. Using the slotted spoon, transfer the sausage to the bowl with the bacon.

Add the onion and garlic to the pot and cook, stirring occasionally, until softened, about 3 minutes. Add the potatoes, bacon, sausage, and ½ teaspoon kosher salt. Stir to combine.

Increase the heat to high. Add 5 cups low-sodium chicken broth, stir to combine, and bring to a simmer. Reduce the heat to medium and simmer until the potatoes are fork-tender, 6 to 8 minutes. Meanwhile, strip the leaves from 1 medium bunch kale and tear into bite-size pieces (about 4 packed cups); discard the stems.

Add the kale to the soup and cook until wilted and tender, 2 to 4 minutes. Turn off the heat. Add 1 ½ cups heavy cream and a few grinds of freshly ground black pepper. Stir to combine. Taste and season with more kosher salt as needed. Serve topped with the reserved bacon and sliced sun-dried tomatoes if desired.