Season the neck bones: Mix salt, pepper, smoked paprika, garlic powder, onion powder, thyme, and red pepper flakes. Rub all over the cleaned neck bones.
Sear: Heat oil in a large pot over medium-high. Sear the neck bones in batches until nicely browned on all sides. Remove and set aside.
Sauté aromatics: Add diced onions to the pot and cook until soft and lightly browned. Stir in garlic and cook 30 seconds.
Make the gravy base: Sprinkle flour over the onions and stir for 1 minute to form a light roux.
Add liquids: Pour in 1 cup broth to deglaze, scraping up browned bits. Add remaining broth, Worcestershire sauce, and bay leaf.
Simmer: Return neck bones to the pot. Cover and simmer on low for 2–2½ hours, stirring occasionally, until the meat is tender and the gravy is thick and silky.
Finish: Taste and adjust seasoning. Remove bay leaf. Rest 10 minutes before serving.