For full independence, why not simply detach development from community?
You can even have multiple independent communities with multiple independent moderation teams all about the same software.
As a developer I've never needed to engage a particular community on a personal level in order to make a PR to a project.. if the technical maintainers want to accept the change, they will, if they won't then that's fine, they probably have their reasons. It's ok to communicate with communities to get feedback, but I'm not making contributions for the social approval, I'm making them when I believe they are useful, and most of the times I write them because I want to have that change myself. If it's rejected and enough other people are interested in the change, it can be forked. That doesn't mean I hate the maintainers or that I don't want the original to exist or anything, it's not personal.
But well, I understand that some communities wanna make software and they intertwine development and social relationships. However, if you do this then I don't see how can independence be a thing. Either separate them and don't intermix them or mix them and don't expect them to be separate.