I actually came across an Eos “webcam kit” at Walmart in-store that came with a USB cable and the AC adapter. Pricey at ~$90, but they did sell it like that.
Since all EOS R series camera's can charge their battery perfectly fine when connected to a USB-C PD charger the only thing that adapter 'fixes' is the software lock Canon placed on the camera which causes it to stop charging from USB when turned on. Smells like a software-defined business model to me...
