With all the wave of hacks that have plagued the cryptocurrency exchange industry over the years, I would back away from staking on an exchange. Of course the entire concept of staking involves a user keeping hold of a large number of coins to gain a small portion of it and it goes without saying that even the top-tier exchanges in the industry have been known to be shaky when it comes down to their backend security.
my advice is to stay away from low rated exchanges that offers staking service, very soon they will claim to offer same service as well,
Goes without saying that the lower tier exchanges will also come up with similar offers in attempts to rotate the 'staked' coins and then the entire operation goes horribly wrong for many concerning reasons.