According to me, Solana, Ethereum, and Cardano are three coins whose prices are well known to climb. Those who have committed in these two will make more, while those who haven't should prefer these three coins. First and foremost, their funds will be diversified, and they will also make a sizable profit since these three are optimistic about the future.
I will choose like you, these are the 3 best altcoins in my opinion. ETH and ADA are sure to have strong developments in the future, and Sol is a blockchain with huge potential, as long as it fixes a few problems, it will be the fastest and cheapest blockchain today. All 3 are well worth the investment as well as using them. If OP adds BNB to the list above, then BNB will also be my pick, BNB is as good as ETH.
I wouldn't really consider SOL as the best, and when BNB is right there, it doesn't make sense to pick something else, it would be wiser to add ETH and BNB together because they are the two biggest names and I would definitely consider ADA as a third, I somehow prefer Avax for some reason but I do not have a powerful reason behind it so I will not support that.
However, I will definitely support that if you have btc, eth, bnb in your portfolio, those three will make sure that you get rich. All the money I can save goes directly into these three and that makes me a lot richer, that gives me a lot better returns so far and I am quite happy about it as well.