In my opinion for long term hold you should go for the top 50 coins on CMC. In particularly the top 10 if you do not want to do your own research. Always insure you keep Bitcoin and Ethereum as your preferred one and whenever possible try to accumulate more of these two.
I agree with you. The right coin choice for the long term, we really have to choose the top 10 market cap, to reduce the risk of losing. Because the top 10 marketcap coins usually definitely go up if the market is stable. In my opinion the top 10 coin marketcap coins are special. But sometimes the risk comes unexpectedly. Before investing think about the risk.