Personally I would not install Numpy into Metashape like that. Try installing it into your Pythons standard package library, then in your entry point Metashape script append numpy installation path to your the sys path.
TL;DR
1. I have packages I need installed - I run pip install <package-name>
2. find the modules / dist-packages location.
3 Then at the very beginning of my python entry point I declare sys.path.append('/usr/local/lib/python3.8/dist-packages')
4. I now have access to that module within my script.
I have not tested this on 1.8.3 but I recommend giving it a shot, good luck!