Another possible issue: arcing/stuff burning on to one of the lightning pins. IDK why it happens, it’s probably lint or something, but it’s easy enough to mitigate: If a cable stops working all the sudden, the first thing I do is wet my fingers and rub both sides of the lightning cable’s connector. Most of the time that does the trick, no new cable or tools needed!
Yep, there's definitely a scorch mark. I already tried cleaning it and the port. It intermittently works and seems to depend on which way the cable is plugged in (still intermittent but better; other cables are usually better but still intermittent).