First- stop believing ANY marketing hype about cables. Coax is fine- even RG59 is fine. For that matter, Cat5e would be fine if you use a decent balun to convert from RJ45 to RCA plugs.
Second- gravity always wins, so don't use a heavy cable and plug with a long strain relief that sticks out horizontally- the weight of the cable pulls down and stresses the jack & plug.
Third- what you find depends on the words used in your search. There is no 'best' at the level most people can afford- 'best' is OK if a small number are being compared (good, better, best) but in absolute terms, it just leads to a rabbit hole and confusion.
If you hear hum with more than one cable, you have a ground loop or a source of EMI (Electro-Magnetic interference). Move the cable way from the existing path and if the hum stops, find a better path that works for your room's arrangement. If you only hear hum when using one cable and can't get it to stop, use a different cable. Any cable with RCA ends, or a piece of coax with F to RCA adapters. If that doesn't work, use an extension cord for the subwoofer's power cord and lug it into the same outlet as the rest of the system. If the hum stops, it shows that the resistance on your electrical wiring contacts is high or the other outlet is on a different circut.
Why do you think you need a better cable?
