Recommendation for an audiophile speaker cord that is not "bright"?

I would also agree with those that recommended the Cardas Clear Reflection. I auditioned them against some speaker cables that I thought for sure would blow them away, but they ended up bettering them.  Not overly warm, and not bright at all, for my system they were just right.

Seriously? (Eye roll) send me your cables and $1000 and ill soak them in my patented anti-bright cable conditioner for one full cycle of the moon and send them back...

Analysis plus crystal ovals might work well for you.  I liked them so much in my somewhat bright/forward system that I ended up purchasing a full loom of their interconnects as well.

they are fairly reasonable price-wise when purchased new, but you can find really good deals in the used market.

https://www.lowesforpros.com/pd/250-ft-14-2-Standard-Speaker-Wire-By-the-Roll/3137563

I have what used to referred to as some of Wilson's least forgiving speakers (W/P 5.1).  I splurged when I found a deal on some used MIT Matrix HD 60 bi-wire cables (for around $1500 IIRC). And they are a match made in heaven with the Wilsons. Some folks object to the retail MIT pricing, but they really are like a component upgrade that makes everything come together beautifully. Wilson and Magico used to use MIT (may still) in  their audio show demos.