Chop all vegetables and have ingredients measured before starting.
Warm the olive oil in a large heavy pot over medium-high heat.
Brown the ground beef, breaking it up, until no pink remains, 5–7 minutes. Drain excess grease.
Stir in onion, celery, and bell pepper. Cook until softened, about 4 minutes.
Add garlic and cook until fragrant, about 30 seconds.
Season with salt, pepper, smoked paprika, thyme, and red pepper flakes if using.
Add carrots and potatoes; stir to coat with the seasonings and beef mixture.
Pour in diced tomatoes, tomato sauce, beef broth, and Worcestershire. Scrape up any browned bits.
Bring to a boil, then reduce to a gentle simmer. Cover and cook 25 minutes, stirring occasionally, until potatoes are tender.
Stir in kidney beans and simmer uncovered 8–10 minutes more to thicken slightly.
Finish with parsley. Taste and adjust seasoning. Let rest 5 minutes before serving.