Sapiens
Polymathematician
Again, no one is proposing, "]origin by spontaneous accident, sheer fluke, random chance, whatever term you prefer." That is your warped view.origin by spontaneous accident, sheer fluke, random chance, whatever term you prefer, - 'why' provides a power of explanation nature alone lacks, and solves what is otherwise a paradoxical infinite regression of unguided mechanisms.
"Why" provides nothing or everything, but is entirely irreverent to survival and/or success. If you are happy with fables and myths ... great, keep them under your own roof and out of the agora, or at least when in public don't pretend that they provide some cosmic insight. Your particular suite of "whys" leads into illogical and unsupportable places where you are able to pretend that the paradoxical infinite regression problem is solved by the introduction, in defiance of parsimony ,of another layer of this time supernatural infinite regression that is no better explained than the previous natural one.
You would be better served to search out integrative answers than to simply paper over the existing natural mysteries with a plethora of supernatural mysteries.