Go for big projects, because they are good for long-term investment such as ETH, ADA, BNB, SHIB, XRP, etc. You could search for more that suit your budget. Everything is in the dip right now so buying is a really good choice in my opinion. I just wanna remind you that trading in stock means you have a lot of patient to wait for the right time to sell for you to maximize your profits in the long run.
ADA and XRP aren't good coins to invest in. While the rest of the market was giving huge return last bull cycle, neither gave a good enough return. This project are basically dead. XRP has a lawsuit against them and got them delisted from many exchanges as they're been called a security and nobody wants to be associated with them or risk getting investigated as well.
ADA is basically useless as we'll be having better layer 1 projects and nobody is using the cardano blockchain, we have Solana, polygon, Ethereum and even Binance smartchain that are better than the cardano blockchain.