It seems like a clarification of what exactly the VDH license is would help you. Click
this:
https://groups.google.com/g/video-downloadhelper-q-and-a/c/BzPLK2YyL-s
There's lots of useful stuff in there that you should read, if not today, eventually.
Relevant to this situation, do a string search for "philosophy" within the text of that
web page. That will reposition the page to a reference that contains a link. Click the
link & read what you find. You will learn the VDH for Chrome does not download content
from YouTube. This is not a technological restriction. Michel could easily have written
VDH for Chrome to download from YouTube. But Google does not permit it. So VDH for
Chrome is legally prevented from downloading from YouTube. As for transferring a VDH for
Chrome license to VDH for Firefox, that is also explained in the reference you will read.
Do make the effor to read that. It will be most helpful.