Ok briefly observable but not anymore and never will be. And galaxies can move faster than the speed of light: https://m.phys.org/news/2015-10-galaxies-faster.html

I was going to correct that technicality on observable but was on mobile earlier.

Also you can absolutely have a theory that explains the observable universe reliably (i.e. Verifiable) but at the same time makes suggestions about the unobservable universe (for example most cosmos theories say the actual universe is bigger than the observable). We just don't have the technology or time to observe it yet.