@isoparme your steps 1 and 2 can be replaced with my updated Helper Libraries. The original libraries have a page that details how to setup VSCode in a little more detail than my now outdated post that you linked. You will also find a link to my Python stubs which should ease development of Jython rules.
You can find my updated libraries in this post:
https://community.openhab.org/t/ivan-s-helper-libraries-oh3-python-javascript/