Sugru is a good idea! It has a limited shelf life - 13 months, apparently, unless you keep it in the freezer - so you can’t just have a packet lying around forever. Like we did. But we did mend a dishwasher bracket thing.
Cables breaking at attachment points is a tricky problem - if you add something rigid, you move the problem. You need something springy or semi-flexible. My laptop power cable is in a right state. Found a few possible ideas on thingiverse, anyway: