The best thing to do with github is to make a release and provide a zip file “ready to use”
It’s what I do when I update a new plugin release
Example:
=> I upload the zip, ready to use
=> Github build the source code automatically (because source code in github contains more than you need in plugin zip file)
Personally, I stop to watch a video after 2minutes… here your first video was 45minutes and I have t confess that I didn’t look a her, that’s too long.
An installation procedure should be few step described as text, it’s easier to follow 
I started to wrote a plugin manager few month ago, it was able to manage properly zip content, but i didn’t try to continue…
No idea for now… the only one thing I can see, if API doesn’t provide any information, is to analyze krita window content (but I’m not sure if transform tool is a QWidget or if it’s something paint over window area)
Grum999