Not sure if you really mean EXTENSION cable, as opposed to simply a longer SINGLE cable.
Just to be clear, an extension cable is one which has a female connector on one end and a male on the the other end. When using an extension cable you would need to use a standard lightning cable connected to the extension.
If that’s really what you mean, you’re generally better off with one cable of 10 ft, for example, than two combined cables adding up to 10 feet. Partially because you have a chance of added resistance from oxidation on the additional connectors with an extension
Thanks for clarifying.
Basically I have a Brodit cradle that comes with an integrated cable that ends in a USB male connector I want to extend this cable as the USB plug to CarPlay is located to far away from where I want to mount the cradle.