0% at exchanges. If you look at the history of exchanges, they are not safe for long term storage. And if anyone - like Celsius, FTX etc - is offering something that appears too good to be true or wants to have custody of your coins, it probably is and they are probably scammers.
Anyone who is offering a higher percentage in your bitcoin holdings is obviously telling you to hand your bitcoin over to them, and they are trying to use someone greedy to steal from them.
Once bitcoin is sent to a centralised exchange, the custody of that fund is no longer in the hands of the owner; the bitcoin now has a new owner, and all that the person gets is just some figures added to their account and nothing more than that.
The question most people need to ask first is: how and what exactly will this exchange offering this reward do with the bitcoin, which will increase the reward over a short period of time that will be enough to reward both depositors and keep their business going?
NOT YOUR KEY NOT YOUR COIN. No matter the kind of offer Celsius and FTX give, it's not worth handing them over your custody of your coins.