Do you believe that unskilled labour doesn't exist?

I don't think labor can be measured by skilled versus unskilled. There are some tasks that are lower in difficulty, but they're often significantly more challenging due to scale. I'd argue mowing a yard is not particularly challenging, but doing that for 8 hours a day as a professional landscaper, the entire time experiencing the harshness of the weather, is a much more challenging job than an 8 hour shift as an accountant. At least in my opinion.

I like the idea of identifying how work is challenging. I've heard it said that work can only be compared within it's primary challenge type. For example physically taxing work, mentally draining work, or urgent reactive work. Welding vs tile laying, marketing vs event coordinating, law enforcement vs fire rescue, etc.