If you could arrange for a object with a fixed period of varying luminosity to be present in every galaxy (think of it as a clock), then I’m pretty certain we would observe a lengthening in that period which would be a function of the velocity the galaxy appears to be receding from us, which in turn one would compute from the degree to which the object’s spectrum is redshifted (and this in turn being a function of distance). The farther a galaxy is from us, the faster it appears to be moving away from us due to metric expansion, the greater the redshift and the greater the dilation we observe in their clock.