How to use a branch to merge with multiple branches

[Sayan Talukder]

i have a prod and qa branch for respective environments (in bitbucket) to deploy my changes.

now when a developer wants to pull in their change in bitbucket and target qa and then prod what they currently do is create a branch from qa and on the same branch they pull in their changes from their dev environment,post which they raise a pr and deploy to qa

now when they want to move the changes to production they create another branch (this time release as the parent) and pull in their changes from the dev org to this new branch and then deploy their changes to production.

Is there a better way to manage this situation?

NOTE:i can't merge qa and prod branches as they might have additional set of files present in qa which are not moved to production.