Hello there @Reede971!
Per your provided log and background, the issue is most likely isolated to that particular project, indeed. A similar scenario was encountered in the thread below, and the solution was to migrate the contents to a new project:
Alternatively, you can try clearing the project’s cache, via deleting the following folders from your directory:
- Binaries/
- Intermediate/
- Saved/
- .vs/
As per the potential problem with StarterContent, you can force the file’s re-creation. Simply delete StarterContent.upac from the FeaturePacks directory. After that, right click your install in the launcher, and choose Verify, which will force a fresh download.