I was partially successful using IPluginManager::MountNewlyCreatedPlugin | Unreal Engine 5.4 Documentation | Epic Developer Community (epicgames.com). I could copy the plug-in after the project was loaded, it wasn’t recognized by the Editor and when I used the call above it mounted the plug-in and I was able to access the contents.
To make this work dynamically and outside the project folder I would furthermore need to either make this work with a directory hard link or add a new search path for plug-ins if that is possible. The hard link works but not dynamically meaning it has to be in place before the Editor starts. Creating it while running does not work.