Basically the best coin to mine now is ETH pretty much, it has the most profitability on a weekly to weekly basis. Sure you can switch coins and algos from day to day to earn maybe 10% more but most of the time its not worth it.

You can mine ETH and sell it for some other alt coin you want to buy. However keep in mind many alts are down 90% and people keep waiting for this alt season and it never wants to come. So becareful investing anything in alts. If you want to invest then just buy the top 10 alts.