I asked around for some help with updating the graphics, and got some incredibly good results that I was very happy with, so many thanks for the suggestion!
Hopefully the new graphics help with differentiating the different tiers of machines (though mainly in terms of the entity itself), the number of arrows in the recycling logo on the icon might not be the most noticeable thing in the crafting menu/inventory, but it should at least be more noticeable than it was before. Implemented in v9.1.2
If necessary, I do have a potential solution in place to help differentiate the icons, that I can still add at any point, even with the new icon graphics.