I have developed an app for a customer a little over a year ago. Now that my iTunes membership has expired, the app is pulled out of the app store.
Is it possible to transfer the app to another account? Apple just makes it so difficult to find answers.
The answer here is pretty simple:
You cannot do anything if your membership is expired. They will remove your app from the AppStore and you will not be able to access AppStoreConnect anyway so there is no way to transfer it.
Perhaps you can reach out to their support to achieve what you're looking for.
Hope that helps :)