to be honest, in my opinion, the Top 100 coinmarketcap is a profitable altcoin, because the top 100 certainly has a large trading volume and is listed on a large exchange, it's good for altcoin, and it's not wrong to hold it

Now even in the top 100 there are some problems, still it is better to choose the coins that are higher and carefully study them, before investing in them, personally I am now considering only the top 20.
you are absolutely right about the top 20 altcoin, since coins with a rating of below do not inspire confidence, since many altcoin are supported primarily by speculators in the cryptocurrency market and may not have real prospects in the future for real use. Today, investments should be treated with caution and more carefully examine each coin and analyze its prospects.