If we cannot detect what’s beyond the CMBR, then there’s no evidence to support any scientific claims beyond that limit. We have reached the limits of science. Anything beyond that is purely theoretical.
Here is the summary of my logic in arguing we are at/near the center of the universe:
1. We observe the CMBR to be uniform in its origination and detection.
2. The CMBR is the earliest remnant we can detect of the Big Bang.
3. If the universe is Euclidean and spherical, then the only place we can detect a uniform CMBR is near the center of the universe. If we were closer to the edge of the sphere, we would detect a non-uniform CMBR.