Same for me. I installed addict in the HariCardGenerator plugin folder (C:\Program Files\Epic Games\UE_5.6\Engine\Binaries\ThirdParty\Python3\Win64), but then it wants pytorch. So far I had to install these python packages:
numpy PyYAML scipy Pillow opencv-python addict
I am sure after I install torch, it will want another package. But I should not have to install these packages, it should find these packages because I have the Python Foundation Packages plugin installed. Frustrating.