House edge is the only avenue where the gambling industries are using to make their own money, though this charges varies from websites to websites and the percentage also differs however 0% house edge gambling site should not be trusted because they will eventually scam you.
very likely that the house manipulating edge them to attract players to come in, see a lot of players looking for edge low to be a gamble for them, then do not be surprised if a lot of gambling sites vying race to have the edge is very low, but if one of them said that they have the edge 0%, I can assure that they are crap and maybe will scam you