Tower Plus EBT2250, 1000W PSU adapter cable needed for Nvidia 5080 GPU

<Moved out of Precision board and into Dell Pro board. DELL-Admin>

I have the Tower Plus EBT2250 with a 1000W power supply and would like to install a Nvidia 5080 GPU. This GPU has the 12VHWR plug and comes with an 3x8 PCI adapter. The PSU has 2x8 power output cables and 2x6 connections that are pigtailed off the 2x8 cables. Can I use a 2x6 female to 1x8 male adapter to power the third PCI plug for the GPU? Will the power draw be too great on the 2x8 cables and cause problems? Any advice or solutions would be greatly appreciated.