I believe that God is singular, because ultimately I believe that there can only be one source for all of creation. If there were to be multiple Gods, this would then suggest in the need for a creator for these multiple Gods to explain away the duality of it all. When it all boils down to it, the only way to truly explain the existence for anything is to eventually come to the conclusion that everything in creation must have all come from one common source. A source that was never created by anything, a source that merely just exists and that always has been and always will be, and a source that is essentially beyond anything else, this is what I believe God to be.
That's just wrong though. If you're assuming that there's this thing that exists with no beginning and no end, then there's no reason that there should be only one of them. Unlike normal things that are limited by lifespan, resources, etc. a being that has always been and always will be has no such limitations. Without limitations, there would be an infinite number of such beings, because there's literally nothing stopping that from being the case as long as it's possible for there to be at least one.
So your options for number of these beings are zero, or infinity. One is not an option.
The truth is that God or source has no explanation for it's existence, it just simply just exists, it is what it is. It's confusing at first because the human mind perceives things in terms of duality, and the idea that God just simply exists makes absolutely no rational sense at first to the mind. The human mind demands that there must be some sort of explanation for Gods existence, but the ultimate truth is that there isn't an explanation. God just exists, therefore reality just exists.
This is not correct. That might be how your mind works, but most people are completely capable of accepting the existence of something without understanding why it exists or how it came into existence.
The pushback you're getting is against the idea that one would believe in the existence of something without clear evidence of that thing existing. The universe existing is evidence that the universe exists, not of God.
And so what is the explanation for "The Big Bang"? There was nothing, and then all of a sudden the physical universe just popped into existence all by itself? Right, because that makes a lot of sense...
I'm assuming that you're using "The Big Bang" as shorthand for "how did the universe begin?".
It turns out that it's actually okay to admit that you don't fully understand something. You don't have to make up an answer just because you're not sure.
"We don't know how the universe started, therefore it must have been God" is a terrible argument, and makes about as much sense as
"We don't know how the universe started, therefore it must have just popped into existence from nothingness".
I can tell you the most obvious answer as to what existed before the Big Bang, that answer is and always will be God.
Why is that obvious? If it's obvious, it seems like it would be easy to lay out the explanation in a logical manner. But as far as I can tell, the properties of the Big Bang as we understand it are such that we're unable to make any clear statements about what things were like before a certain point. And even if we ignore obvious inconsistencies in our understanding and draw them out to their logical conclusions, we end up at a point where the entire concept of a reality breaks down and we have literally no idea if even basic things like "existence" are possible.
Again, there's nothing wrong with admitting that you don't fully understand something and just because you don't understand doesn't mean God did it.