We are all out of our depth. Even when Einstein demonstrated that time and space are relative, neither he nor anyone since has been able to explain what cannot be explained by our understanding. If we are wedded to certain concepts such as time, cause and effect and triggers, we introduce false variables.

To say something triggered the Big Bang requires time before time existed.

It isn't my subject either. But I have enough knowledge I suppose to say that if the Big Bang is to be discussed, you have to discuss the Big Bang. Which means that time does not predate it.