The OP should beware of the leap of faith.
It is undeniable that the First cause argument is one of the stronger theist ones, though it essentially a gap for god argument - if we can't explain it, then Goddunnit has to be the answer.
It doesn't. And arguments as to why we can't prove that a god isn't there is not the basis of the atheist position. It is more that it isn't HERE
so far as convincing evidence goes. If there is a creative entity out there it could be pretty much anything we could imagine and likely something we can't.
Which is why paintings of an old man in a byzantine robe sending down divine authority upon his self -appointed spokesbods is at best symbolic.
Religions have nothing to do with a possible first cause. They are man - made systems of belief intended originally perhaps to come up with an explanation for "Who made Everything, Then?", rather admit the truth: "We don't know." but because a handy tool for bolstering Authority, first of rulers, then of religions and finally of individual bods trying to run people's lives for them.
High time for an end to it.