Hi @QCyapudetofu16, I tried packaging a blank project just now on 5.7 and did have some compile errors. However it was a different error than shown in your image.
After checking in the forums, it suggested that I update my visual studio. After updating the compile errors went away.
I was then able to compile a blank project with BlueprintAssist enabled.
Although the error is different, perhaps updating Visual Studio will also fix the problem you are having?
For reference, this is the compile error I was seeing before updating