This sounds very good! I am particularly impressed with being able to use maxima to create questions that have a random element. I wish I'd had what you have done back at the start of the pandemic when I had to create quizzes for my moduless.
In answer to your actual question: no, I do not believe you are off the mark. I no longer have a need for what you are doing but I'm sure others would benefit greatly if they have to interact with moodle and its xml formats etc. -- : Eric S Fraga, with org release_9.6.13-1003-g872c1b in Emacs 30.0.50