The Hubble law is widely used as distance ladder. Edwin Hubble assumed that the high redshift of far away galaxies was caused by their speed, which led to the expanding universe. He never imagined that a redshift of more than 1 would ever be measured. How about relativity: Doppler at ultra-high speeds and gravitation?
A step back to the distance-redshift observations, leads to an advanced Hubble law and a distance ladder for high redshifted galaxies. No ‘Dark energy’ needed, cosmic inflation explained and a space-time ‘Hubble horizon’ emerges.