A few of the things you want to assume are dead end thought paths that make any reply illogical. Pointing that out, however is, ironically, logical.
If you'll admit to even the smallest possibility that any of your suppositions are incorrect to even a tiny degree, again, ironically, the reply becomes almost infinite in the range of possibilities.
So then my answer will be as distilled as possible if anything exists out of nothing, someone must know how to create a set called nothing. Then be able to make the set of everything come forth from the nothing.
Let's call this the creator, for lack of a better term.
So that I understand you, aside from recognizing a creator, meaning the creator of everything including the nothing it proceeded from, that creator's purpose for bringing forth intelligent life is not for all to know, and you want to exclude all ideas of collective cosmic theoretical dogmas and ethereal trademarks.
I get it. No guys or women ringing bells and chanting slogans.
But you want at least a reasonable sales pitch to explain why each one is a priceless and profoundly rare gem only to exist in one place in time?
That could be an excessively loooong conversation but it should suffice to say that not many would want to make the required life's work of it.
The one guy that ever did got pinned to a cross.