Is there a GitLab web view that can be integrated into a PHP site?

I’m currently thinking about an idea and I need your assessment for this. I have a page where people can create projects. Now I want to offer something new: GitLab.

My idea was that I want to create a Repo and a User in GitLab (and assign the user to the project) as soon as someone creates one on my page. For that I want to use the GitLab PHP API.

When everything is set up, I want to create a folder inside this new Repo - also via the API. Now I have the plan to make this folder visible inside a frame on my page - like a minimal view just for this folder where people can upload, view or edit stuff. But when visiting the Repo in GitLab directly, the whole Repository can be viewed.

Does anyone has an idea if this is possible with GitLab at all? I want to use the infrastructure I already have on my server.