I think you might be right about the repo being misconfigured. I saw on the official UE4 perforce documentation: Using Perforce as Source Control | Unreal Engine Documentation that you should add only a few of the project folders to the repo. However, as you can see here:
We’ve got a few of the other folders included too. Could excluding these from the repo enable a correct build? Thanks for helping btw, I really appreciate the suggestions.