All altcoins are different. A lot depends on altcoins and the demand for them. First of all it is necessary to develop a project and create demand for it. If the project is useful has a developed an ecosystem and a lot of users the demand is such a project will raise and the price of the tokens will raise too.
I think that the best altcoin for investment is Ethereum because a lot of meme coins, DeFi and NFT use Ethereum blockchain.
Also now is a very popular Binance Smart Chain. It means that BNB is very prospective too.