I don't use Chrome so I can't help you with making it install properly there. I can
perhaps answer some of your questions about the license. Click this link:
https://groups.google.com/g/video-downloadhelper-q-and-a/c/BzPLK2YyL-s
You'll probably want to bookmark that for easy reference. You might look through there
on general principles. You might find something worth reading. Specific to this case,
do a string search on "philosophy" in there. That will give you a link to click. Read
up on what the license does & does not do. It also explains why there are different
licenses for the different browsers.
I do hope you get your Chrome issue sorted out. There's plenty of users on here who have
successfully installed VDH on Chrome & use it all the time. That says it should be
possible for you to eventually get it working.