Can we improve the documentation for the app router auth handler?

[jonschmidt]

Checklist

• [X] I have looked into the Readme, Examples, and FAQ and have not found a suitable solution or answer.
• [X] I have looked into the API documentation and have not found a suitable solution or answer.
• [X] I have searched the issues and have not found a suitable solution or answer.
• [X] I have searched the Auth0 Community forums and have not found a suitable solution or answer.
• [X] I agree to the terms within the Auth0 Code of Conduct.

Describe the problem you'd like to have solved

There is pretty good documentation for the nextjs pages router, but I think the documentation around the app router could really use some love. It is after all going to be way more popular going forward as it is the recommended way to build apps.

Describe the ideal solution

I would love to know more examples of how to customize the auth handler. I am specifically lookfing for how I can set the returnTo parameter dynamically for the various routes, so I can pass it in from the caller via the url params

Alternatives and current workarounds

The current version actually seems to work by using the examples in the old pages router, but it actually is using the wrong types (NextRequest vs NextApiRequest)

Additional context

No response