Summary
expo-router package only loads pages that are directly in the /app directory.
Many projects end up having many directories (like /types, /utils, etc.) and managing them is easier when you put your app's code in /src directory.
That's why I think supporting /src/app directory for pages is really important - eg. see NextJS, it allows you to use /src/pages structure.
Minimal reproducible example
https://github.com/PiotrekPKP/expo-router-test
This should work and not show the default router layout ^