What is the best way to distribute a project with shared code and unique 3D models / data connections?

Hey all, for a project I have been working on with a friend we are looking into ways to distribute to clients in the most efficient way, but we are unsure what the most efficient way is here.

We are creating a platform (subject is architecture) and want a unique building for every distribution based on the same platform code. However, it is not just placing a 3D model in the project since there are also data connections that are unique for each building.

What would be our best approach to create and manage different distributions for different clients? We ofcourse do not want a complete unique repo for each distribution, because managing and updating that would be a pain when the amount of distributions grows.

I highly appreciate any help or links to other pages regarding the same topic.