There is no intrinsic reliable argument that one cannot have encountered god.
Or leprechauns, or ghosts, or fairies, or aliens, or...
You also seem to have forgotten that there are
many, many different gods that are often mutually contradictory.
This is not true for having encountered strings, superstrings, the multiverse etc, simulated universe or the other big answers and theories of everything usually and openly and admittedly associated with guessing.
Well some of those are attempts to construct testable hypotheses, others are guesses, some with more credibility than others. Most of them at least have some sort of starting point in what is known. Not sure what the point of bringing any of them up was, though...
Again religion claims God first and foremost and isn't science.
You appear to be equating religion with monotheism but in the middle of this car crash it hardly seems to matter.
So, in summery, you don't have any way to distinguish religious claims about objective reality from guessing and your accusation of a straw man was false.