I just received this information from the Raspberry Pi Foundation: Exclusive: we've just released 13 new online computing course pathways.
There are over a dozen computing courses available free. Most of them do not assume a Raspberry Pi computer. Maybe some of this material will be helpful to you. There are several subject matter courses and a couple of courses on the pedagogy of computing, one for ages 5-11 and another for ages 11-16.
These are FutureLearn courses, and there’s a price given for each one. However, they’re free if you work straight through each one. For example, a three-week course is free for three weeks. If you want to take longer, it will begin to cost money, so don’t start a course until you’re ready to work at the pace of the course. Also, don’t start a bunch of them at once.