I have a processor that already requires two PCIe connectors on the motherboard. However, MSI has now recommended the following cable: Corsair Premium 600W PCIe 5.0 / Gen 5 12VHPWR Power Supply Cable - Fits Type 4 Power Supplies via Two 8 Pin PCIe Ports - 12+4 Pin Male
Why don't you just use the supplied 2×8pin PCIe cables? The power supply offers enough connection options, unless you are using a processor with more than 200W power.