I understand that you can’t use both USB ports if you have the rear one hooked to the wireless dongle. If you unplug the dongle from the rear USB can you then use the front USB with carplay? Or if you have the rear USB you have to use this one only for carplay?
This is a question about the working principle of a USB cable. For any USB cable, only the end of it can work as a USB device. Therefore, after you extend the front USB to the rear USB, the front USB will no longer work.
There are 4 wires in the USB cable, which are 5V+, ground wire, data+, data-, data+ and data-can only work for the end USB device.
When the front USB is inserted into an external device, the rear USB will stop working, and the front USB can only be used for charging.