As always, very much appreciation to Dan_WGBU (our favorite engineer).
Unsaid but implied is that his method should let your motherboard be happy and not demand a F1 Enter stop, and still let you use those rear USB3 ports coming straight off the motherboard to the rear backplane.
My method will turn off all USB3 ports and make them invisible to the OS and the motherboard. Dan's approach is better, and his cautions are well worth heeding.
Scott