Cook the chopped bacon in a large skillet over medium heat until crisp. Remove the bacon with a slotted spoon and set it aside, leaving the drippings in the pan.
Toss the beef cubes with the flour, salt, and pepper. Brown the beef in the bacon drippings in batches, then transfer it to the slow cooker.
Add the onion, garlic, carrots, and mushrooms to the same skillet and cook for 3 minutes. Stir in the tomato paste and cook 1 minute more.
Pour the red wine into the skillet and scrape up any browned bits. Let the wine simmer for 2 minutes, then transfer everything to the slow cooker.
Add the potatoes, beef broth, thyme sprigs, bay leaves, and cooked bacon to the slow cooker. Stir gently to combine.
Cover and cook on low for 7 to 8 hours, until the beef is fork-tender and the potatoes are soft.
Remove the thyme sprigs and bay leaves before serving.