Where did the universe come from? Atheistic origin science has no answer.

[pocaracas]

A table begins to exist, because someone converts wood into a finished product.
A cloud begins to exist because heat from the sun causes water in the ocean to evaporate and accumulate somewhere in the atmosphere.
A star begins to exist when a cloud of hydrogen, through the action of gravity, clumps together so tightly that the hydrogen atoms are forced to fuse creating helium atoms in the process and releasing a lot of energy in the form of light and radiation.
Etc.Etc.Etc...

Anything that we're commonly aware of has a precondition that results in that thing.

The counterintuitive science has discovered that some particles can, occasionally, be created out of quantum foam, a virtual field (or fields ) which have no real expression except when they cause such real fields (like particles).

The universe may have come into existence through such quantum foam... or some other process that we are not aware of yet.
Regardless of the potential mechanisms for it, we weren't there, so scientists will be hard pressed to convince ignorant indoctrinated imps... we can only hope that future generations will not be so ignorant and, as a result, will not be so indoctrinated.

Did the universe have a beginning? Perhaps...Some people may tell you that the big bang also created space- time, for both those dimensions become null at the singularity... others may tell you that the singularity was simply compressing pre-existing space-time into one point and then expanded that. Some may tell you that other similar singularities (like those found in black holes) can sprout other universes.
The truth, however, is that we can't say for sure if the universe had a beginning.

So, premise one and two are faulty...your conclusion, however logically accurate, is also faulty.
There's your Gibraltar stone...

if your argument is angling towards that universe came from 'nothing' that would be accordance with the historical christianity belief in creation ex nihilo. that is: all matter, energy, time, and space previously didn't exist --- no preexistent physical reality.

No... the clue was on the "perhaps".
We don't know enough to say that your premises are true, so your conclusion is not guaranteed to be true.

In fact, it seems that all matter and energy of the known universe came from that quantum foam...not ex nihilo.