Prep the oven and pan: Preheat the oven to 400°F (200°C). Line a sheet pan with foil and set a wire rack on top for even crisping.
Trim the tenderloin: Remove any silver skin with a sharp knife so the seasoning penetrates and the texture stays tender.
Season well: In a small bowl, mix salt, pepper, garlic powder, smoked paprika, and onion powder.
Pat the pork dry and rub with Dijon mustard, then coat with the spice blend on all sides.
Wrap with bacon: Lay bacon strips slightly overlapping on a board. Place the tenderloin across the strips and roll to wrap, seam-side down. Tuck ends under or secure with toothpicks.
Sear for crispness: Heat oil in a large skillet over medium-high.
Sear the bacon-wrapped pork 1–2 minutes per side until lightly browned. Transfer to the prepared rack, seam-side down.
Roast to temperature: Roast for 20–25 minutes, until the thickest part reaches 140–145°F (60–63°C) for juicy, slightly pink pork.
Optional glaze: In the last 5 minutes, brush with the sugar-free maple syrup or erythritol-vinegar mix for a subtle sheen and tang.
Rest and slice: Rest 5–10 minutes so juices settle. Slice into 1-inch rounds and sprinkle with thyme.