Very few sharpening machines can cope with anything other than a flat blade so they are limited to non mulching blades for a start ( Gators excepted ).
The angle is nowhere near as important as people like to think.
The draught is created by the flutes on the blade and the blade angle is the minimum that provides support to the cutting edge.
or long life & optimum cut what is important is the thickness of the flat edge.
Too thick, you get tearing and put extra load on the entire cutting system
Too thin then the edge gets deformed easily and wears away rapidly.
Like sharpening knives, soldering , welding, plaining wood etc, these are hand eye skills that you attain through consistantly doing it.
Once you start using jigs & quides you loose those skills.
I can hand file a chain saw blade, faster and finer with no guide than I can do the same job with the blade grinder.
How ever is there are 50 of them then the grinder gets plugged in.
This is a skill I developed over many years.