I think I lost the crypto I had in my stormgain exchange account (StormGain has migrated its operation to the platform powered by YouHodler)
From now on I think I will only use exchanges that are on the top 50 or 100 by volume... or if you have other suggestions/filters when choosing an exchange?
You have made a mistake, especially since you are holding your cryptocurrency on an exchange. You should have known that a central exchange could fall into a bad situation at any time. That's why you should have stored your cryptocurrency in your wallet instead of storing it on an exchange.