Hey Sean,
I agree to Martin @MVall and would add that it is always the best to buy the spindle cable ready-to-use with the spindle from spindle manufacturer. Reputable spindle manufacturers always offer this.
PwnCNC is one of the rare dealers that offer a kit nearly ready to use and they also offer ready-to-use spindle cables separately for the chinese spindles that don’t offer a cable (but just a loose connector)
Another manufacturer that offers spindle/VFD kits ready to use is Mechatron (see here) (Unboxing video). There are many more spindle manufacturers but Mechatron is often mentioned because they also address consumers. They even have an ebay shop.