What's wrong with having $200 in ETH? It's already a good investment.
It seems to me that you need to make investments in the cryptocurrency that has the most stable exchange rate. I advise pay attention to the size of the withdrawal fee, so that you can withdraw your income at any time without much loss. In general, everyone will recommend a coin that they like.
Maybe when talking about coins that have the most stable exchange rate so far I think it refers to bitcoin or ethereum, for coins other than the two I don't know more and it's better to learn more about cryptocurrency to understand everything