Between a Node 2i and DAC: Does Coax cable quality really matter?

+1, fuzztone.
The only way to know by trying couple of cables in your setup. I say this, DH Labs makes very good digital cables. Here are couple of recommendations,

https://www.tweekgeek.com/audiophile-cables/oyaide-db-510.html
https://audioenvy.com/product/home-car-pro-interconnects/digital-coax-3ft/

I can send you the AE Digital Coax for you to try. If interested, PM me your address.