Is it better to keep good project coins for holding?
or
Trade in spot/ futures market in less leverage.
It depends on market. Likewise, this time if you had bought altcoins, you will not sell at down price, so you have to wait more to see the green market. Ultimately, in this situation, I will suggest you for Hold or if you have still funds for trading purposes, then this is the best time for trading. Market will recover the prices soon.