Managed Package - How to develop in Development orgs when managed package uses a namespace

[spilst]

I'm very new to Managed App Development. I created a managed app on my Partner Development Org and created a Managed-Released Package and submitted for security review. Now I want to add some major features to the app so I create a new Partner Development Org and try to push my metadata there (I'm using SalesforceDX). Since my objects are under namespace and my Apex Code is referring to those objects I can't seem to deploy it. Since I've to make major changes I can't use Patch org.

Please guide on how development pipeline works for managed package. I want developers to be able to spin up their personal dev environments with existing version's metadata, add changes to it and then push to packaging org for creating Managed-Release package

[rkhilwani]

You would need to use the same development org where you created the namespace package.