Dark horse options for much less than one might think:
Belden 4731R RG11:
Canare L8-CUHD RG11:
Both are 12G-SDI cables. Very stiff, but literally bleeding-edge signal carrying ability for coax. Easy to find with BNC connections. B&H Photo carries them, along with Markertek others. Add some 10-11mm clamp on ferrites of the correct freq range, and you’re good to go.
Been using each on my Qutest as single BNC input cables from my GAIA DDC. They both absolutely shamed: a Wireworld Silver Starlight 8, a AQ Carbon & Coffee, and an Audience Studio One.
I understand that clock cables carry a different signal from S/PDIF, but I thought this information might be helpful.
One caveat: both the Belden and Canare required a very long break in.