"Gearbox MK01" is required to make "Automated Factory MK01" and "Burner Assembling machine 3" is required to make "Gearbox MK01" because "Automated Factory MK01" is not available at first.
Eight different SPs are required to unlock "Burner Assembling machine 3".
Is this detour intentional?

Wow, I have made a mistake.

I check recipe info of "Gearbox MK01" by Mod of "What is it really used for?", it shows need "Burner assembling machine 3" or higher.
However, that was a mistake, and when I checked the recipe for the gearbox in the list of recipes in the inventory, I found that I could make a gearbox if I had assembly machine 2.