I have a problem with Epic Games. When I access the unreal engine library, the engine that I downloaded does not appear in the library, nor do my projects, such as City Sample, but they are on my computer. Now I want to add some materials to the project, but they do not appear in my projects.
You may have two different folders for launcher cache, or two different launchers installed.
Find where assets and engines are stored, compare to settings in LAUNCHER.