10 million cash instantly would get you killed so fast, just look at ANY article about lottery winners getting their life just absolutely fucked up. Resetting at 6 would suck too but at least you would get something out of it.
It's not so hard to put it in the bank and hire a wealth management firm. They'll take care of you and tell you how much you can spend each year without losing money. It'd turn into a free $500k salary for life.
It really isn't that easy but you are on the right path. First thing you have to do is convert it into a form that nobody is able to withdraw quickly. That removes all almost all incentive for greedy/desperate people to try and kill you for it. Good luck doing that with 10M in cash, though. Large volumes of money are nowhere near as mobile as you think it is.