As a pos coin, Dash is a great one for long term investment and ETH is definitely the best one after choosing BTC. But eth won't be able to surpass bitcoin in the current markets. In future , it may be happened because of more adoption than the adoption rate of Bitcoin. As far from the history, not only eth's price but also other altcoin's price is mainly depend on the Bitcoin's price movement. So we just need to wait for the bull run of the Bitcoin and after that we hope to see the altcoin bull run.
if you want to minimize the risk, just choose bitcoin and ethereum. maybe dash, bnb, and other popular altcoins also have potential, it's just that the risk is still too big compared to choosing bitcoin and ethereum. for this reason, I think everyone has their own reasons for choosing bitcoin and ethereum.