Preheat the oven to 425°F (220°C) and line a sheet pan with parchment paper. Combine granulated garlic, salt, pepper, thyme, and smoked paprika in a small bowl.

Pat pork tenderloin dry with paper towels. Coat all sides with half of the seasoning mixture, rubbing it into the meat. Let the tenderloin sit at room temperature.

Combine apples, red onion, and sweet potatoes in a bowl. Add the remaining seasoning mixture and melted butter, mix well, and spread on the prepared baking sheet.

Roast the vegetable mixture uncovered in the oven for 10 minutes.

Meanwhile, melt the remaining butter in a skillet over medium-high heat. Brown the tenderloin on all sides for 2–3 minutes per side.

Place the browned tenderloin in the center of the sheet pan with the vegetables and return to the oven. Roast for another 10–15 minutes.

For the glaze, add apple cider, red wine vinegar, and Dijon mustard to the skillet. Boil until reduced to about 1 cup. Spoon over the tenderloin and vegetables.

Roast until the thickest part of the tenderloin reaches an internal temperature of 140°F (60°C), about 5–10 minutes.