How to avoid herbs getting burnt in the oven
Add the flavouring later in the cooking process

e.g. For a 7 minute cook; at the 4 minute mark, remove from oven, brush/spray with oil and sprinkle on flavouring (herbs etc), and quickly return to oven to finish cooking

Experiment with the time point, you are trying to crisp the bread, and bake on oil/herb mix

Commercially each flavouring is applied at it's own time point. Salts early, soft herbs and spices later