if you ask which altcoin, I will answer the altcoin in the top 10 coinmarketcap which has the potential to increase significantly and can provide a lot of profit. however, to be more convincing you can try to do an analysis of these tokens
Top coins are definitely a good choice to trade. But since the market cap of top coins is large, even if the price of these coins increases, it will be less than the coins of other low market caps. Before buying any coin, you must know about that coin. I agree with you that it is possible to make a profit by buying the top coins, but the problem here is that if the market trend changes to the negative then even the top coins will not help you.