What you're describing has a name. It's "God of the gaps"
I know that's still the valid argument against deism (and pretty much the only one honestly...) and y'know what...'god-of-gaps' argument does make sense in that by conceding to a supernatural possibility, you won't advance science that way. Science is always about finding the unknown.
BUT the 'god-of-gaps' argument as a fallacy can also be said to be a fallacy by itself since it's attempting to rule out a god as a possibility in the first place. Which you can't disprove either.
Furthermore is there no limits to science? There are some things I dont think science can ever explain. Perhaps the supernatural can be explained too if we're willing to let go of the constraints of science like falsifiability.
God of the gaps is less of a fallacy and more a methodology. Yes, science can't always prove the absence of something, although "evidence of absence" can be used to rule out the possibility. The point is that it will be impossible for you as a deist to explicitly define the bounds of what this God is capable of that is beyond science, because in a hundred years or 500 years or a thousand years science may discover new founding principles that break those boundaries. But without creating explicit bounds on your creator, it is nothing more than a collection of unanswered questions.
but that's it, you assuming science is in itself, boundless and can keep advancing. See, all of us are hypocrites. And what's worse, the question of 'why?' will keep remaining. Even if scientists somehow...manage to miraculously create life out of non-living matter, it still begs the question, 'why? why is the universe just so happen to be ripe for life forms?' and neither will it disprove the existence of a god being behind the creation of creation. Even if we somehow find an intelligent alien life 1000 years later, it still begs the question, 'who created us?' or even the alien says 'I created you, bro', the alien has to ask, 'but who created me?"
and a creator would be, by right, boundless, because like the argument that goes... 'who created god?' can be matched with 'god is infinite'. In the same way, you could ask 'what created the universe?' and the athiest can only reply back 'the universe is infinite.'
Is it an impossible-to-refute stance? yes it is. But is it an impossible stance? No, it's not.
Not quite. I am not assuming that science is boundless, but rather that the pursuit of science has an as of now unknown bound. It's a subtle but important difference.
Also, it's an unreasonable assumption to believe that there is a "why" for everything. If your worldview requires a God to bypass the possibility that some things just "are", then that is a human limitation and not a scientific one. ---
"History Is Much Like An Endless Waltz. The Three Beats Of War, Peace And Revolution Continue On Forever." - Gundam Wing: Endless Waltz