First cause, appearances and mind

Im asking about the Vajrayana or Mahayana view, but theravadan views are fine too. Buddhism rejects a first cause, but how can birth and death go in infinite regress? How did samsara start? Ultimately nothing arises yes, but then there would be no movement or action, right? The only way I can posit a solution is the cyclic universe theory where mind and appearances have always existed, and are dependent upon each other. Thus they can be said to give rise to one another in a sense (but not in succession, just that without one the other cant exist). I think this is what Guru Rinpoche also said somewhere? Is this the Buddhist view? By the way, I have recently converted to Buddhism after having debated it in the past. I want to understand it more, so this is not an attack on buddhist Pratityasamutpada. This is very hard for me to understand. I am hoping someone more knowledgeable than me can provide some insight. Edit:I think I have found an answer with the theory of the Five lights in dzogchen.matter and consciousness(wich is a element)are always there,and have always been there.