Which git structure to choose for partner site engine?

Question

git

We create an engine for partner sites. The git structure is as follows:

• master - main engine
  
• master-dev - development branch
  
• master-dev-feature, master-dev-feature1, ... - additional branches
  

For a partner site, the git structure is:

• partner - master branch
  
• partner-dev - development branch
  

We pull the functionality from master to partner-dev, add a theme to partner-dev (yii2). In partner branches, there should be no change in functionality. Number of branches: 2*n-partner branches and k-engine branches. Moreover, there can be more than 20 partner sites. I immediately look forward to the contamination of the git repository.
What git repository structure should I follow for easier deployment and easy engine updates?

Answer 1

Why not separate the common core from the main site and partner sites into a separate package and include it as a dependency with the composer here and there?