Is this wiring between two USB-C connectors (receptacle) valid?
Your problem is not that reversal is invalid, but that a USB C female to female coupler is invalid.

All but the most basic USB C cables (3A USB 2.0) rely on an electronic marker inside the cable to detect the capabilities and orientation of the cable. Coupling two cables together is not a supported configuration.

If it's for your own use only and you only need USB2 then you may able to get away with connecting all four CC pins together, then using basic passive cables. You should still be aware of the potential for up to 20V on Vbus.