It is strange for me that man with such sum searching an advice from the unknown members. With such money i don`t see a problem to find a specialist for analyze. I even can`t imagine anybody with such sum searching such information himself. It can be some assistant hired for searching such information or just fake, i don`t know for what purposes.
He didn't mention if the 45 millions was in dollars so let's give him the benefits of a doubt as any individual with such money in dollars shoudn't be looking for advice from some random individuals on the internet. The only advice I can give the OP is to only trust crypto casinos or sportsbooks that have a presence on the forum with very good reputation. OP have you considered using multiple platforms since that'll be too much for one site to handle.
If I had that type of money I won't be comfortable wagering them on one platforms as casino are getting hacked, I'll be using more that one platforms to play it safe so if one platforms got hack, I can have backups with other account and to avoid bringing attention to myself as that's a huge money to use on one site.