My understanding is that Einstein said relativity neither proves nor disproves the aether. I’m wondering if you’ve read Frank Wilczek? My understanding of current physics is there is no such thing as empty space, in quantum vacuum there is still zero-point energy. Wilczek has much to say about the contents of the aether, the quantum field, or what he calls “the Grid” and cosmic superconductivity. As you comment about the empty space idea in relation to your Infinite Universe theory, I’m thinking you’d be interested in these ideas.