I am right-handed, but I learned to shave with both hands. When shaving WTG (north to south), I shave with the hand on the same side of my face. When shaving ATG (south to north), I find it far easier to shave with the opposite hand.

My chin is shaped like a golf ball, including some of the dimples and there is no clear grain direction, the hair stick straight out in some places. I have found the best way to shave my chin is to shave two passes with a straight razor and then make a final clean up pass using a DE razor.

Like you, I am retired, but I have found that if I go too long before shaves, my beard becomes even tougher than it is normally, at least for the first pass. Thus, I would suggest you try shaving every couple of days and see if that improves your shave. Make sure you use a good shave soap that creates a slick, protective lather.