Same problem here, 4 Bug repots made in the same problem:
- Fortnite Crash in Push Changes and Project Stuck in Checking for if the project can be uploaded - General / Issues and Bug Reporting - Epic Developer Community Forums (unrealengine.com)
- Timeout after Pushing Verse Changes - General / Issues and Bug Reporting - Epic Developer Community Forums (unrealengine.com)
- Project Stuck in Checking for if the project can be uploaded - General / Issues and Bug Reporting - Epic Developer Community Forums (unrealengine.com)
- Revision Control stuck in: Checking for if the project can be uploaded (UEFN + Fortnite restart needed on each Push Changes) - General / Issues and Bug Reporting - Epic Developer Community Forums (unrealengine.com)
Managed to get it to work by reintalling everything but 1 week later the same problem happens.
This only ocurrs in large projects with a lot of code/memory at least in my experience.