Bitcoin and Ethereum are beneficial for long-term growth, which gives you stability and wider adoption with an established market presence and infrastructure like ETFs. You can even buy them through special funds now. But they might not grow as fast as newer, smaller cryptocurrencies.
On the other side, small cryptos Solana and Polkadot will grow much faster as they have new and intriguing technologies. Their prices can change quickly, which makes it unpredictable also. So, it's advisable to research carefully before investing. It's better to diversify your investments to get more returns and reduce the risk.