Preheat oven to 400°F (200°C). Line a rimmed baking sheet with foil and place a wire rack on top. Spray the rack lightly with cooking spray.
In a small bowl, combine olive oil, minced garlic, lemon zest, 1 tablespoon lemon juice, rosemary, thyme, smoked paprika, salt, and pepper. Stir to form a loose paste.
Pat chicken leg quarters extremely dry with paper towels. Loosen the skin gently with your fingers, then rub half the herb paste directly onto the meat under the skin. Spread the remaining paste all over the outside of the skin.
Place seasoned leg quarters skin-side up on the prepared rack. Nestle the reserved lemon half (cut side up) on the rack beside them. Roast for 40–45 minutes, or until an instant-read thermometer inserted into the thickest part of the thigh (not touching bone) reads at least 165°F (74°C) for safety, ideally 170–175°F for extra tenderness, and the skin is deep golden brown.
Remove pan from oven, tent loosely with foil, and let rest 10 minutes. This allows juices to redistribute. Transfer to a platter, squeeze the roasted lemon half over the top, and garnish with extra fresh herbs if desired.