I'd say you can do almost anything except the specialist software stuff. By specialist I mean "brand stuff"; for example, the problem with a photo editing course is that instead of teaching you the principles, they often teach you how to do stuff in (say) Lightroom, essentially compounding the problem. I understand why they do this -- it cuts corners and assumes a common ground; supporting a multitude of editing software the instructor might not be familiar with would be a nightmare -- but it doesn't help the situation.

If they taught you the principles of editing photos, without using brand specific names, you could do this with GIMP or Krita.

I do hobby stuff with my Linux laptop, by the way :)

If they didn’t show how to do it in specific software then I don’t think the majority of people would get it.

Agreed. Though I think the main problem is that an instructor cannot be expected to provide guidance for a dozen different tools. I understand the problem, I just wish they could approach this from an angle of general principles instead of specific tools.

This is something I don't think enough people consider. There's a very long tail of niche software for niche use cases, and even "casual" computer users are likely to end up needing something from that very large set.