Time is the rate of change of something. The rate of change varies with gravity(

Time is the rate of change of something. The rate of change varies with gravity(density) and velocity(density), and apparently increases in their absence (entropy) but what is the lowest rate of change in the quantum background? And does that rate of change (where we already know that the rate of ‘boil’ in the quantum background is so fast it’s unimaginable) reach a minimum rate of change: a zero point with which to measure all other rates of change as a ratio?

Reply addressees: @AutistocratMS