First let me say I am fairly new, about 8 weeks into this. You have mentioned many of the variables essential to a comfortable shave, but one thing I haven't seen you mention is the way you pull the blade across your face. Do you just move the blade in a strictly vertical line? There is a Barber's manual I have read that advocates a motion of the blade in the horizontal direction at the same time as the vertical direction. I'm not sure if this is what is meant as 'Scything'. The motion I use will move the blade about 3/4" in the horizontal direction for a pass down the cheek, about 3 inches.
Also, as for comfort, the blade has to just barely touch your face.
I also agree to trying a disposable, just to eliminate any question of blade issues.
Have you shaved with a DE? How does that do with your beard?
I have a thick beard on the chin, especiall the white hairs, which are twice as thick as the others. I am finally getting to the point where I am almost BBS there, takes about 4 passes.
Hope this helps.
PS, what area are you located, and can you find a local Senior Member to mentor you?