All dependencies are distro / system dependencies, not pip dependencies (even if we develop in a venv).

This is to make deb packaging easy where we list system dependencies.

wxPython - https://shanemcd.org/2020/05/03/how-to-install-wxpython-in-a-python-virtual-environment-on-debian-buster/

A couple of the key steps (there are others but you may have already done them):

sudo apt-get install build-essential python3-dev \
  libwebkit2gtk-4.0-dev libtiff-dev libnotify-dev \
  freeglut3-dev libsdl1.2-dev libgstreamer-plugins-base1.0-dev

And in venv (when activated):

pip install wxPython