About 30 minutes before cooking, remove pork tenderloin from the refrigerator to bring it to room temperature. Remove any excess fat and silver skin.
Preheat the air fryer using the "Air Crisp" function, setting the temperature to 375°F and the timer to 25 minutes.
Mix half the olive oil with dried rosemary, garlic powder, and onion powder in a bowl. Season with salt and pepper, then brush this mixture onto the pork.
Toss diced potatoes with the remaining olive oil, rosemary, garlic powder, and onion powder. Season with salt and pepper.
Once the air fryer indicates it's time to add food, place the pork tenderloin inside and surround it with the seasoned potatoes.
After 10 minutes of cooking, flip the pork and stir the potatoes for even browning. Continue cooking for another 10 minutes, then check the pork's internal temperature.
Remove the pork when it reaches just above 140°F and let it rest for 3-5 minutes to allow residual heat to carry it to a safe temperature.
Finish cooking the potatoes for the remaining time.
Serve the sliced pork tenderloin with the roasted potatoes and Roasted Garlic Cream Sauce, garnished with fresh herbs if desired.