from this post discussing resistance of Li vs. Pb batteries. We know Li has lower internal resistance than Pb; there is no need to exaggerate the effect.
> A totally dead[lead] battery will instantly read 14.4 volts when charging
It will not.
At C/2.5 charging (max for quality AGM) from 50% DoD it takes about 20mins to reach Vabs==14.4v, at which point ~13.5Ah will have been replaced. (source)
At C/5 charging (max for FLA, min for AGM) it takes about 76mins to reach Vabs=14.4v, at which point 26.7Ah will have been replaced.
So it is not instant and the battery is not “completely dead” when Vabs is reached.