Which is more efficient to connect your middleware with a full graph and then create the subgraphs for the client or directly have the subgraph and connect in the middleware?

Hello everyone, I am trying to create a middleware between my server side (Magento) and the client side (Next js), here when I implemented the federation and subgraph were super powerful, my question here is the following:
Which is better to connect to the full graph and create small services in the middleware then in the gateway I will have another full graph that the client can communicate with, is it more efficient if we split Magento in subgraphs as well or it is same if we keep the full graph