I can relate well to this. As a child in school, writing was awful (still is problematic). Over my
early years and being taught to write I found I could write backwards, mirror style, or could do any number
of styles (slanted, printed, cursive) but all of them pretty scruffy or illegible and a cause for complaint
from others. Had years of being told off, made to do things over, work ripped up and generally made to
feel that if only 'I would try harder' it would be fine. Sadly,despite trying it didn't happen surprise, surprise.
Then came something of a majorly enlightened response which was definitely lateral thinking on
the part of one of my teachers. In my last years at secondary school, I and a couple of others
were taken aside and told we were to be doing typing lessons before school (this was the early 1970's - computers in schools were still the stuff of science fiction). This was because as he said we might find we needed to write in our adult lives and this was his solution. Admittedly we had to start school half an hour
early but we were taught to touch type using office typewriters.
Outside of this class mind you, nothing changed, still had to write and be complained at, but after leaving
school and buying a portable typewriter (recently saw one like it in a museum display - that makes me feel old)
it helped me for the next few years until the computer became common. Seems odd now in the era of the word processed school work and can't see why they don;t teach everyone this vital skill.
I have often said that this was the best subject I every had - it taught me to touch type
and that has remained with me for the last 40 years and meant that apart from the odd thing
I can type what I need to write easily and it is accessible to others.
Must be something of heredity in it, my son's writing is also dire. He doesn't bother with the spacing between words, used to write boustrophedon style (lines reversed like ploughing a field) and usually all in capitals.
It may not be diagnostic, but lots of people with ASD seem to have problems with this, however, there are
the others who don't - so who knows, but I am now reassured because it has a fancy name - dysgraphia
so we can sleep easy in our beds.