Just to explain ... If you have a cloned library in the solution it is simply a Visual Studio shared c++ project. Therefore the question is really about Visual Studio.

If I understand the question then the answer should be this:-

Remove the shared library project from your solution by right-clicking it in the Solution Explorer window and choosing Remove. Move the entire project folder, including subdirectories wherever you want it to go. Add the project back to your solution by right clicking the Solution > Add Existing Project. (You will see a file with .vcxitems extension, that is the "project" that needs to be added)

After you have moved and readded the shared project, right click the "References" node of an Arduino project name in the solution explorer. Select "Add Reference". In the "add reference" dialog click "Shared Projects", the project you moved will appear in the list. Check the checkbox and close the "add references" window.

That should describe how to remove and re-add any shared library project to a solution.

One other point, in the solution explorer (not all files view) you can right click and "Add New Solution Folder". "Solution folders" do not actually exist, they are virtual. They allow us to organise projects and external ancillary (files such as docs) regardless of where the files are actually located.