So regardless of physics, quantum physics and opinions about what reality is and how we came to exist, and what exists out there. The universe means everything, so saying there is more just means it is included.
I know the present day use is drifted more to mean the galaxy, but originally it meant everything conceivable (and inconceivable). Hard to explain by text and in another language. But universe originally meant everything in existence, including time. Not just the world and galaxy we live in.
like I say all there is, you say there is more, well then it is still all there is.