Define "minimum".  There are always risks to custodial platforms.  Once your bitcoin is signed over to someone else, it isn't yours anymore.  Bitcoin is not debt-based, so it does not naturally generate interest.  If a custodian service cannot clearly explain the business model which allows them to offer interest, you should naturally be very skeptical.

Alternatively, if you wish to discuss staking Proof-of-Stake coins, please refer to the Altcoin Discussion board.