I dont think there is a tutorial directly for what you are asking or trying to achieve.
However when you said a Pluggable Widget, that seems like 1 of the ways through.
Since a Pluggable widget is nothing but a HTML/JS being shown inside Mendix pages, why not do below.
Make a Pluggable widget (default options)
in the root .tsx file return the HTML block that your plugin provides (not the while HTML but just the block which is needed)
find a react package for your external library (or perhaps make one if you cant find one) and install it as a dependency in your plugin react code
try to get the JS object of your library in the React code
See if by then the desired outcome can be reached. I know its a long shot but worth the try.