What altcoin / altcoins would you choose and what would you invest your million in? 
I think the best option now, given the risk-to-return ratio, is:
$NEAR
$FLOW
$DOT
I think the best option now, given the risk-to-return ratio, is:
$NEAR
$FLOW
$DOT
Its more better to first consider the risk in making an investment on altcoins before investing $1,000,000 into any altcoin, if it were to be be bitcoin, i may not exercise doubt or fear, you can remember that its not advisable to invest all your asset on a single coin, but its a wise decision if you split the money on more than one in other to increase your chances for profitability and reduced rate of risk on loosing the entire asset on a single investment.