If ever I have that large amount of money, I will use this capital in different altcoins in which I know it would really give a nice profit in the future. And one of this are Rev, Pundix, Matic, Corx, Bsc, Utk, and more that has a development now in the market.
Diversification is good but if you are starting, I think that it is better that you invest it in only one like bitcoin because most altcoins that @martina14 mentioned needs some research first. Remember to concentrate on one and then slowly diversify.