Short answer: No, this isn't possible.
If you host your course on another platform like Teachable, just point your people there to buy the course and sign up there. The Convertkit Products feature is really best for things like ebooks, coaching, presets, files, etc. You could re-format your course to be a single PDF with links to the videos? If you did that, you could use the Products feature! If you want to keep things separate, a course platform is probably a better fit.