Have you tried leaning forward when doing the sideburns/cheek? Non-dominant hand just takes more getting used to than the dominant hand. If you're new you gotta stay cool with your temporary limitations.

I don't own a hanging strop (only paddle). Maybe folding it the opposite direction.. or pressing it flat with something for a while?

Experience will help through the thick parts of your beard. Reduced angle and great stropping (truer edge) will contribute significantly to success. Also, remember once you really tackle the heavy bearded areas that you don't have to do completely XTG, you can shave diagonally as a combination WTG/XTG.

Can you shave without your glasses? Shaving a blur isn't fun, but you can always check up on your progress with non-razor holding fingers and redo missed hairs/parts.

My sensitive skin has been sensitive forever. The best thing to happen to my skin was shaving with a straight-edge for consecutive shaves. Only possible once I'd built up the skills to not overly irritate the skin and with proper pre-shave preparation. Salicylic acid face washes, regular washing of the skin and solid post-shave routine including alum block, witch hazel or skin tonic and after shave balm helped. Now the lower half of my face is smoother and the complexion is cleaner than it's been since the onset of puberty. My skin is definitely conditioned/tougher and takes str8 and DE shaves better than ever before. There is definitely an adjustment period for people with problematic skin. Hang in there.