This could be helpful, but considering the number of HTTP Outcall BE canister needs to perform, the price is gonaa be really expensive.
HTTP OUT calls are not cheap! Specially when you need to perform quite a lot of them.
Besides still everyone could perform that call and there is no way of guaranteeing the call os coming only from the frontend.
The best way in my case is to only rely on BE canister with a lot of validations, there is no secure way of trusting FE.