All loot boxes are chance based, but first of all, I don't know which laws you're talking about. Brazil's? Guessing the US because when somebody has a case of the default human it's typically an American, but who knows.
But also, I'm not a US lawyer, but I seriously doubt US gambling laws requires all games to have a flat probability, mostly because... that's not how games of chance work anywhere, and definitely not how blind boxes work anywhere and blind box products are not gambling anyway, which is the entire point.
It's still a non sequitur and I still have no idea what you're trying to say.