ALL explanations come to an end eventually. If the physicists figure out how those elementary particles arose, then it will lead to another question. That's just how it is. And having God as that final answer would not stop a religious scientist from trying to answer as many questions as possible about the origin of the universe.
A religious scientist who believes a God as the "first cause" is not thinking scientifically. They're beginning with an answer (God did it) and finding evidence to support that and dismissing that which seems to contradict. That, or they're compartmentalizing, which is further demonstration of their failure to think scientifically and accept evidence.
Additionally, there very well may be an end after which there are no questions. I'll say it for the perhaps fifth time -- the Universe doesn't care whether or not we think it makes sense. We evolved to understand a world where things have causes, not to understand the very deepest fundamentals of the Universe. The world's religions were created in a time when people had an extraordinarily limited understanding of the Universe, so it makes sense that their apologetics are limited by that scope.
Religion and science cover largely different domains. Learning how something works is vastly different than ascribing meaning to that thing. Science deals more with the former, while religion deals more with the latter. I don't know of any religions that claim to have all the answers. Which religion are you referring to? Does the Qur'an have an ayah on the histopathological differences between UC and Crohn's? Because I'm actually tryna learn that at the moment.
Obviously religion deals with applying meaning to the world. That's one of the primary reasons it was invented in the first place, because humans have a need to exist with meaning and we apply meaning to our environment due to several cognitive biases that we evolved to possess.
Again, religion absolutely claims to have all the answers. This portion of your post is ignoring what you quoted. When Islam was created, there was no understanding of disease processes at the tissue level, so it's absolutely stupid to say something like that. They did, however, know of what we now call epilepsy, for instance. Their answer -- demon possession. If someone has some other debilitating disease or they couldn't have children, they were perhaps cursed. Religions created answers to questions that were accessible to them.
Religions also make claims about the nature of reality, as does science. I'll reiterate -- science is a much better way of knowing that is religion. The claims it makes are vetted and founded in evidence and the predictions it makes about the Universe can be substantiated. It is self-correcting and is constantly trying to "prove" itself wrong. Religion does none of these things, expect make claims, which are unsubstantiated, unreliable and founded on dogma and faith, not evidence and the rigor of the scientific method. "A wizard did it" is a bad answer, but it's essentially what religion offers.
Say new data arises that makes it highly likely that irreducible complexity actually is a valid argument. If you're boxed-in as an atheist, then you run into some problems. Therefore, I think agnosticism is a more defensible position
Say that new evidence arises that unicorns are real -- us unicorn non-believers sure would be boxed in then! What are you talking about?
Atheism is the position of not believing that god(s) exists. It is not a claim that god(s) doesn't exist. It is a negative position, where as religion is a positive position.
Theist : "I believe in God."
Atheist : "I don't believe that."
This proposal that atheists are somehow dogmatic is just an
ad hominem tu quoqui.
Agnosticism is perhaps a useless designation of null belief. I'm not certain it's possible to hold a null belief about something when you look at evidence or lack thereof. I'm not entirely convinced that agnosticism by itself is a meaningful concept.