>basic reasoning tells you that there is a sphere beyond which is outside our light cone, and yet outside which the universe still exists.

Of course, but basic reasoning isn't evidence. Again... "evidence" implies something that can be observed, and something that can be observed, by definition, lies within the observable universe.

>Are you saying the observable universe is bounded to our Hubble volume?

I'm saying the observable universe is bounded to what we can observe, and evidence of something beyond the observable universe is a contradiction in terms.

I don't know how I can possibly make it simpler.