Infinite Causality Fallacy

Hello Rabbi,
The cosmological argument is based on the fact that there are two possible situations:
1. An endless chain of reasons
2. A stopping factor we call ‘God’
As I understand it, the rabbi claims that there is a flaw in the first option. The flaw is that in order to present an explanation for the question, one must present all the factors of the answer. Therefore, we will accept the second option.
I couldn’t figure out what the failure was. First of all, of course we presented the entire explanation. We just claimed that the explanation was infinite.
It seems that the rabbi is linking lack of knowledge to a logical fallacy. A logical fallacy really cannot be an explanation, but saying that there is another possibility that I simply don’t know what it means can be an explanation.
Just because a person can’t grasp the concept of infinity in their mind doesn’t mean it doesn’t exist. It’s simply a lack of knowledge. And in any case, it can be an explanation.
What does the rabbi think about this argument?