Heat a large pot or Dutch oven over medium-high heat. Add the olive oil and ground venison or ground beef. Season with kosher salt and black pepper. Cook, breaking the meat apart with a spoon, until well browned, about 8 minutes.

Reduce the heat to medium-low. Add the butter and let it melt. Stir in the diced onions and minced garlic. Cook until the onions are softened and fragrant, about 3-4 minutes.

Sprinkle the flour over the meat and onions. Stir until no dry flour remains and everything is coated. Cook for 2 minutes, stirring often. Add the tomato paste and cook for 1 more minute, stirring constantly.

Slowly pour in the beef broth or venison stock while stirring to avoid lumps. Add the red wine and fire-roasted tomatoes with their juices. Stir to combine.

Add the carrots, celery, potatoes, bay leaves, dried thyme, fresh rosemary, paprika, and mild chile powder. Stir well.

Cover with a lid and bring the stew to a gentle simmer over medium-low heat. Cook, stirring occasionally, until the potatoes are just fork tender and the carrots are soft, about 30-40 minutes. If the stew becomes too thick, add a splash of broth or water; if you'd like it thicker, remove the lid for the last 10-15 minutes.

Remove the bay leaves. Stir in the fresh parsley. Taste and adjust seasoning with more salt and black pepper as needed. Serve hot, garnished with extra parsley if desired.