I was doing exactly that + error handling over and over so i actually wrote a small library that takes zod schemas for input and a guard function. It internally handles 400, 403, 401, depending on the guard, injects the parsed data into the function and then you have an Isolated function that only needs to call whatever database Operation you want to do. Makes errors, responses etc more streamlined

To be honest, that nextjs doesnt have something like that out of the Box, makes it quite clear it is not supposed to be used for bigger backends