Could you explain how we could do it any different besides taking 5 mins to pick a winner?
Just make it so the calculation takes longer than the game takes to run.
Also the only claim to us not being provably fair is the house doing transactions, you can check any of the hashes used. most the time its in the $1000s i have even seen a 1.2 million dollar transaction i don't think anyone is going to send 1.2 million USD to rig a game where you make $0.04 lol
You don't have to spend any money other than the fee - you can just send the million USD to one of your own addresses. And again, the sums involved don't matter. "provably fair" means that you can't cheat. It doesn't mean "we can cheat but why would be bother because it's only 4 cents".
But we see your point where even if it is not economically profitable, and extremely hard to do there still is that chance.
I don't think it's even very hard. If there are only 3 transactions per second, I could send 10 transactions in that second and have a 10 in 13 chance of winning. That tips the odds massively in my favour if I do it every time. Currently it's not worth it because nobody's playing for anything but dust. But I guess you're hoping that sooner or later people will play the more expensive games, at which point you want to be sure that it's not exploitable - or people will exploit it, if only to show you that they can.