Pat beef dry and season on all sides with salt and pepper. Sear in batches in hot olive oil over high heat, 3 to 4 minutes per side until deeply browned. Transfer to slow cooker.
Cook onion, carrots, and celery in the same skillet over medium heat 4 to 5 minutes. Add garlic, cook 1 minute.
Deglaze skillet with red wine, scraping up browned bits. Add crushed tomatoes, tomato paste, and beef broth. Stir and bring to a brief simmer. Pour over beef in slow cooker.
Add oregano, thyme, smoked paprika, and bay leaves. Cover and cook on low 8 to 9 hours or high 4 to 5 hours until beef shreds easily.
Remove beef to a cutting board and shred coarsely with two forks. Return to slow cooker, stir into sauce, remove bay leaves, and taste for salt.
Cook pasta in heavily salted water, reserve 1/2 cup pasta water before draining. Toss pasta with ragu, adding pasta water as needed to coat. Serve with fresh basil and parmesan.