First you need to decide what kind of coin retention period you are talking about. The practice and experience of most traders indicates that the portfolio for the long term may contain only one name of the coin - this is bitcoin. As for alts, now it’s probably the time to go against the temptation to acquire altcoins for a long retention period. Today it’s worth checking every source of information. There are many biases. The reward is most likely not worth the risk.