In Dependent Co-Arising, is Dukkha a Sankhara, a Vedana, both, or none?

How should I understand dukkha (in all its amplitude and semantic complexity), if I want to see it through the lens of Dependent Co-Arising? Where is it classified, apart from the final nidana? Is it a sankhara? Is always something felt and, therefore, a feeling? If dukkha is always something to be felt (as vedana), then does that mean that everytime the chain of conditionality gives rise to the final nidana, the chain "starts again" in vedana? Thanks in advance for your time. Kind regards!