I found a solution to this, it’s not perfect but works.
I created a new project… just called it "project name"2. Once it opens up. Close out of it, and delete everything in it, except the blue UE icon for launching it. Then copy of all of the content from your current project (from the file explorer, exlude the blue application icon).
Then, in your new project file explorer, delete the binaries, build, derivedatacahe, intermedietes, saved and source.
Then open the project, all of your content shoudl be there and it should play normally in editor. Then before you package, you need to create a “dummy” C++ file. So go to file → add C++ class → select class “none” → just call it test or something… this force UE to generate some sort of file. Then package, and it should work, at least it did for me.
if you have a lot of custom C++, this might not work, because I needed to delete the source file, but you could try no deleting source.
Not perfect, you have to basically migrate over to a new project… but I got it to work without recreating anything, so not too much loss/effort