Why don't you choose both? I think you should take 70% of your investment to hold ETH for 1-2 years. Currently, should invest in ETH because the value is low. ETH is the most valuable altcoin currently available, it will have very good prospects for future development. HODL and wait patiently.
The rest you invest in short-term transactions with other altcoin, set reasonable profit targets and sell as soon as you reach the goal.