If you are having trouble figuring out which (alt)coins to invest in now, then I would advise you to invest only in Bitcoin and Ethereum. Basically, though, it's better to invest in fewer coins rather than more.
You probably can't make the really big profits with it, but Bitcoin is currently 40% below its alt-time high and Ethereum around 35%. Should both coins reach their ATM again at some point (which I personally assume), then you can make 65+% in profits.
Simple calc:
Bitcoin ATM was 68k, now 41k what is -40%. If you invest now and Bitcoin goes back to 68k some day, then you make a gain of 65%