I hope I am wrong and you come back in a year from now to prove me wrong but I think it is 99.99% impossible to turn it into $1 million just by buying and holding.
altcoins are not known to go that high in long term (2000%) but they surely they go up a lot in short term which means by trading them during their rising time you can make a lot of profit.

for example a hot coin these days (which is coming to its end of line) is RDD. you can see it has always been dropping constantly in long term even went to 1 digit satoshi values. now it is being pumped towards 100 satoshi and 3 digit satoshi values. this is a ridiculous amount of profit but only gained in a couple of weeks. this will disappear in the long term like 1 year.