Yes it is normal to invest in projects VCs invest in because VCs invest in major crypto projects.
Certainly possible for top 20 coins to fail. An immediate collapse like Luna is unlikely, but everything outside of Bitcoin (and to a lesser extent Ethereum) is just pure speculation so there's no reason why the 3rd, 4th, 5th, etc largest coin won't fail.
And yes there is a good amount of shift in the top 20 every cycle. In 2024 and 2025 for next bull market there will be a new crop of projects that will get hyped up and some of them will move into the top 20 or top 10. Because it's pretty much 100% speculation once you get beyond Bitcoin that means that newer projects will always replace some top older projects each cycle. This will continue to be the case until we see crypto projects actually start showing real world value that goes beyond bull market fads. You can expect pointless cryptos like XRP, DOGE, SHIBA to continue to drop and new projects to grow larger than them. And smart contract networks platforms like ADA, DOT, TRON, AVAX, etc may drop or may continue to stay among the top depending on their hype levels compared to newer projects in the next cycle.