In a large shallow bowl, combine paprika, salt, garlic powder, onion powder, chili powder, dried thyme, dried oregano, brown sugar (or substitute), cayenne, and cracked black pepper to make the Cajun seasoning.
Add the steak cubes to the bowl and toss thoroughly so the pieces are evenly coated with the seasoning.
Heat 2 teaspoons of the oil in a large skillet over medium-high heat until hot but not smoking.
Working in batches to avoid crowding, sear the steak bites 2–3 minutes per side until browned and edges are crisp; add more oil as needed between batches. Transfer cooked bites to a plate and set aside.
Reduce the heat to medium, add the butter to the same skillet and melt. Add the chopped garlic and sauté about 30 seconds until fragrant, scraping up any browned bits from the pan.
Remove the skillet from the heat, return the steak bites to the pan, and toss them in the garlic butter until evenly coated.
Serve the steak bites warm.