Surely an ideal gas is a hypothetical substance that is no more able to produce matter than is any mathematical concept able to conjure up reality.

IMO, the matter resulting from the Big Bang came from the energy of the BB, which must already have existed in some form.

It is reasonable to accept the BB as the birth of our Universe, but it is much more difficult to argue that it can have been the start of everything.

Nothing can come from absolutely nothing, so something must always have existed. One may call that something "God", "quantum foam", "eternal cosmos" or whatever one chooses, it must always have been there. The BB must have been simply a conversion of one kind of "something" into another.

There never was nothing.