You should learn about cryptocurrencies and their underlying risks before investing in any, because it will help keep you in track when the challenges sets in. However, I think ETH is a good one for investing anytime anyday. Another is BNB, at least the team is super active to ensure sustainability of their platform.
Maybe I am over-optimistic, but I don't see risks to invest in altcoins, right now. For each coin, we can wait for a while to choose the best price to buy it, but current price range of altcoins is perfect to enter with nearly zero risks.