I tested the project but got no issues, also I didn’t touch Windows updates or the driver version… it must be something else… I would suggest to you rollback a driver version if it is not the latest one installed, there was a release for NVidia drivers with optimizations for Fortnite (not the last, but the previous one if Im not mistaken).
I do feel the scene has a timed consumption of resources and the FPS drops like 20 FPS each 2-3 sec aprox.