Whisk together the apple cider vinegar, water, ketchup, granulated sugar, kosher salt, crushed red pepper flakes, black pepper, and hot sauce in a small saucepan.
Set over medium heat and bring just to a bare simmer. Cook 2–3 minutes, stirring, until the sugar is fully dissolved and the pepper flakes smell fragrant; do not boil hard.
Remove from heat and let cool to room temperature, 15–20 minutes. Taste and adjust salt, sugar, or heat to preference.
Use immediately to moisten and season chopped smoked pork, or transfer to a bottle or jar, cover, and refrigerate. For the cleanest, mellowed flavor, rest 4–24 hours before serving. Shake before each use.