You make it seem daunting when you refer to them as altcoins, but you keep various types of altcoins in your portfolio. Your selection is based on factors such as the project's concept, market cap size, trust in the developers, availability on exchanges, and recommendations from trusted influencers. The idea is that if one fails, other coins will compensate. This approach, combined with gradually taking profits as prices rise, has proven to be the best exit strategy over the years.
Take note that i do not keep any altcoins in my portfolio. There is no strategy that has proven to be successful in predicting altcoins, how can you trust some developers, when a lot of them have turned out to be scammers in the past, and if you are investing because an influencer recommends the coin, then that is a crazy thing to do. I agree with the point that you can get lucky with a few altcoins if you buy a lot of them, but what if you don't get lucky.