What Einstein proposed, is gravity curves space inward and in the frame of a galaxy, that is what it does.

Effectively what Hubble discovered, is the space between galaxies curves outward. Essentially he found Einstein's cosmological constant.

It's even accepted that they balance out. Omega=1.

That overall, space is flat.

It just seems everyone is caught up in the details and the politics to see the notion of the entire universe as some singular entity is unnecessary.

The background radiation would be the light of ever further sources, shifted off the visible spectrum and the James Webb has been finding ever more distant, mature galaxies.