@OP talking about stacking, what's I got from the question the reward should be paying from the reward stack wallets and the platform will stack your crypto using their wallets they will take some percentage from your reward stack. Until now there is no casino who provided this service, most of them only provided dividend by holding their own token or investment bankroll.
Anyway, using a third parties service for just do a stack was kind of dangerous thing same as exchange when you store the asset on them. Better to stack your crypto on your personal wallet, rent a VPS and just open your wallet. That's would be safe, rather than store your crypto on third service.