I think the layering is doing more than showing off the pantry. If the rice, meat, and steam management are right, the whole spices can sit in the background and behave like a frame instead of a pile of ornaments.
For lamb, I would try one batch with fewer whole spices and a tighter seal, then compare the aroma after resting. A good biryani should still taste joined up, even if you cannot point to every clove like evidence at trial.