In a saucepan over medium heat, sauté garlic for 30 seconds. Add gochujang, peanut butter, soy sauce, rice vinegar, and cream. Simmer 2–3 minutes until smooth. Stir in chili crunch. Begin adding reserved pasta water gradually (up to 1 cup) until the sauce is silky and coats the back of a spoon. Taste and adjust salt as needed.