You should actually update your service description and ToS to mention the fact you don't represent your own liquidity and instead resell a third-party exchange Gate.io and rely on their AML/KYC policies to avoid misleading people.
Maybe they are using other centralized exchanges, not just Gate.io, but they should clearly write that information in their ToS.
There is nothing wrong in offering such services and charge fees for that, if people are willing to take the risk of being asked for kyc verification from those exchanges.
I think that most quick swap exchanges are operating in similar way, with few exceptions.