Azure Functions authentication doesn't work in pre-production environment

**Describe the bug**

We heavily rely on the auth endpoint in form of the `.auth/me` endpoint as well as the injected headers in the backend. If a PR is created and a pre-production environment deployed, the `.auth/me` endpoint sometimes returns a 404, and the bring-your-own-function backend always returns a 405.
This renders our application technically unusable, what can we do to have the auth endpoint available in pre-production environments and to have the auth information handed over to the backend?

**Additional context**
Backend
- Bring your own functions with EP plan and Node 14
- No adjustment in any authorization settings, the App Service has the default "Azure Static Web Apps (Linked)" provider with 302 unauthorized returns

Frontend
- GitHub based Vue.js application

The whole development process heavily relies on PRs and the ability to preview the application in a live environment before merging with GitHub checks that implement E2E tests based on the pre-production environment (that all fail currently).

**EDIT: I just found the [chapter in the docs](https://docs.microsoft.com/en-us/azure/static-web-apps/functions-bring-your-own#restrictions), where is says that bring your own function apps are "Only supported in the Static Web Apps production environment.".
Are there any plans to fix that, as pre-production environments are somewhat useless currently with bring your own functions?**