I am also experiencing this issue. And unfortunately none of the potential fixes have worked for me.
- I have tried signing out and then back in to the launcher
- Uninstalling Epic Online Services
- Running the Epic Games Store as an administrator
- Deleting \ ExternalActors\ThirdPerson\Maps\ThirdPersonMap\D\SY\Z4CTQ4LG3YV10EKPD0UE8Q.uasset
- Deleting the contents of the vault cache (Mine was already empty)
- Just waiting a really long time and hoping for the best
I also did try restarting my computer at a few different points throughout these. If anyone has anything else to suggest it would be greatly appreciated.