Can something come from nothing

[Neo-Scholastic]

The outside of space and time meme is one that I am personally familiar with because I used it myself when I were a Christian. But from a purely linguistic [ non ontological ] perspective it makes zero sense. Because space and time are features of the universe. And the definition of universe is all that there is. Ergo there can be nothing outside of it since how can there be
something outside of all that there is? So if the entity known as God does actually exist he has to do so within the universe not without it.

You are correct to say that technically of the word 'universe' is 'all that is, was or ever will be", but we've kind of moved away from that definition, That definition is not how people use it today. Now it means a self-contained and self-sustaining physical entity that could be part of a larger totality, e.g. a multiverse. If some version of multiverse theory is correct, then each local universe exists outside the time and space of all the others. Nevertheless, that's not how I think about God, as some entity standing apart our world. I tend toward Panentheism.