I have the same experience when I was a beginner. I bought an altcoin because I thought it could provide a good profit in time but I made the wrong decision. It has no value now. It thought me a lesson that I should choose a coin with good potential. I'm now choosing a well-established coin such as bitcoin and ethereum.
Actually if we want a coin for a long term must better to choose those two coins you mention etherium and bitcoin.
On this year so many altcoins are not trusted they are good for promising but in the end your money to invest on it we will gone like a dust. We all know we are experience on that holding and gain for nothing.