How do you know that thing isn't just a non-sentient force
Because that non-sentient force is also a thing, that also had to have an origin. It also had to be created from and by something. All your logic does, is push the "origin" of the universe back further. You can keep extrapolating your logic back further and further, but eventually, there has to be *the very first thing.* And that very first thing, be it quantum fluctuations or some non-sentient force, had to come from somewhere.
which religion is the actually correct one
This question is like asking police detectives which theory of a crime is the correct one. In some cases, there are many theories proposed, each of which implicates or exonerates different people. Police detectives follow the evidence to figure out which theories can be eliminated, and which ones cannot. They aren't always successful, but there is a method. That same forensic analysis can be applied to the question of "which religion is correct." The question is not unanswerable.
YOUR religion says "There is no God." Can we use forensic analysis to determine whether your religion is correct? Yes, I think so, and that chain of logic is outlined above. "Things don't create themselves."