Drupal 9 does not like the leading URL on the fragment passed to CRM.url. I also made the call more technically correct by splitting the path from the params, and specifying it's a back-end page.
I'm still seeing some items I want to improve; the isLogNecessary method needs to be AuthX-aware, and there are cases where the entity and action seem not to be recorded correctly. I'll address these as they become bigger issues for me :)