Preheat the oven to 425°F. Wash and dry the sweet potatoes, then slice them into evenly sized ⅓-inch rounds. Drizzle olive oil onto a large rimmed baking sheet and add the sweet potato slices, turning them to coat evenly. Make sure the slices are spaced apart and not touching. Sprinkle the cinnamon, smoked paprika, cumin, coriander, red pepper flakes, salt, and black pepper evenly over the potatoes, then drizzle with honey. Toss gently to coat. Roast for 20 minutes, flip the rounds, and return to the oven for another 20–25 minutes until golden and crisp around the edges. Transfer to a serving platter, season lightly with additional salt, drizzle with more honey, and finish with crumbled feta and fresh herbs. Serve warm.