Developer to set up remote server for web development.

My current situation is that I have an asp.net core project which I would like to have on a remote windows server in the cloud
and provide access to remote freelence developers to collaborate on the project.

The remote freelance developers will work on front end development (. cshtml , javascript , css files)

The source code is organizined into folders , where some specific folders have the front end code files .

I would like this development environment for remote front end developer to login and only see the folders I give access to him/her , not the other folders.
The other folders with server side code (c#) will be hidden and not accessible.
The have sensitive inbformaation and intellectual content which I wish to protect.
Of course the front end developer will be able to compile and run the code when doing web development , but in no way see the source code in folders I have limited access to.


I have looked into solutions like :

github codespaces https://github.com/features/codespaces
jetbrains remote development https://www.jetbrains.com/remote-development/

These partially solve my problem.

While they run fron a thin client locally on a backend remotly , I havent found any way to protect specific folders in source code.

I am open to any other solution beyond these commercial solutions, as long as the need to protect source code in specific folders is covered.