Thinking about the original question ...
There is a big difference between the skills it takes to making clothing and other gear - planning, cutting, pinning, sewing, ...
... and the skills it takes to do hand-sewn repairs.
Quite frankly I think sewing with a machine is far easier than making a nice-looking strong repair.
I can do a great job with a sewing machine, but hand me a needle and thread and I struggle to do hand sewing. Does anyone know of a good online how-to and that subject?
Somewhere around the house I have a
Speedy Stitcher Sewing Awl that is made for doing heavy duty repairs. They never seem to look very nice.