I spent a lot of money on my shielded cable to get the "flexible" one. Any issues I've experienced are not related to cable quality.

Any 12g shielded cable (or larger) with 6 wires is going to be somewhat stiff and will require proper clamping. It's not like the 18g or 20g cables used on smaller spindles.

Now there's a better solution with all the 220v-380v VFDs. It makes more sense to run higher power spindles on 380v so you can use a smaller cable.