Preheat the smoker: Preheat your smoker to 225°F (107°C). If you don't have a smoker, you can use a grill with a smoke box or your oven (though you will miss out on the smoky flavor).
Assemble the dip: In a large, disposable aluminum pan, combine the Velveeta, cream cheese, shredded cheddar, Monterey Jack cheese, Ro-Tel tomatoes, cooked meat, diced onion, garlic, and jalapeño (if using).
Season the queso: Sprinkle the smoked paprika, chili powder, cumin, salt, and pepper over the mixture. Stir everything together gently.
Cover and smoke: Cover the pan tightly with aluminum foil to prevent ash from getting into the dip. Place the pan in the smoker and let it smoke for 1 hour.
Stir the queso: After 1 hour, remove the foil, stir the mixture thoroughly to combine all the melted ingredients, and let it smoke uncovered for another 30 minutes until the cheese is fully melted and the dip is hot and bubbly.
Serve and enjoy: Carefully remove the pan from the smoker and transfer the queso to a serving bowl (or serve directly from the pan for a rustic presentation). Serve hot with tortilla chips, baguette slices, or vegetable sticks.