I'm afraid you cannot, because Vercel Functions configurations are through exports in the file, so all the routes on the same file should use the same config.

And on the Next documentation, you can see this: Each route.js or page.js file takes over all HTTP verbs for that route..
Source: https://nextjs.org/docs/app/building-your-application/routing/route-handlers#route-resolution

i.e. you can't define the same route with different verbs into differents files

There's probably a way to do that with middlewares, but I wouldn't recommend that