I recommend you choose Bitcoin or Ethereum. The crypto money market is hard to predict, but I see more and more large corporations investing in Ethereum and Bitcoin which makes them relatively stable.
I think, at this time all coins in the top-20 at CMC is the best coins for investment, because the price of Crypto is now being dropped drastically and I Think this is the best moment to buy more potential coins and we make it as a long-term investment.