In that scenario (Holding 500K for the period until autostaking ends) your total earned stakes would be 2,000,000, plus your 500K initial balance would give 2.5M at the end of the period.
You an use the calculator
here to get the following:

Great, which exchange the best place to buy HTZ with less fees for withdrawing? Is there another place to create a web wallet other than on the HTZ website?