Not many coins are you going to buy? I'm not sure that while you keep some of these coins they will not disappear but still if you take 10 coins, then you need to buy them not in equal parts. For example, Bitcoin 50%, Ether 10% and the rest are divided into equal parts.
I can't imagine crypto-portfolio without Bitcoin in it, with the highest percentage! Every crypto-portfolio is a nice
portfolio, don't get me wrong, but with Bitcoin and Ethereum in it it looks much better! After all they are top coins
that last for years and make progress more then others.