Cut each tenderloin crosswise into 4 steaks. Wrap each with a strip of bacon, securing it with a toothpick; season with salt and pepper.
Sauté turkey with 2 tablespoons oil in a sauté pan over medium-high heat until golden brown, about 3 minutes per side. Turn filets on edges and brown the bacon all around, 3–4 minutes. Turkey is done when it reaches an internal temperature of 165°.
Let turkey rest 3 minutes, then remove toothpicks.
Heat 2 tablespoons oil in same pan over medium-high heat. Stir in garlic and pepper flakes; sauté just until fragrant.
Add spinach, tossing with tongs until wilted; season with salt.
Serve turkey with lemon wedges to squeeze over meat and garlic spinach.