I need a remote charging cable

The Siri remote uses a Lightning cable.

Charge the Siri Remote - Apple Support

There are two cale variations. Either USB-A (rectangular, larger, only plugs in one way), or USB-C (oval, smaller, plugs in either way).

You’ll need a Lightning to either a USB-A or USB-C connection, depending on what socket is on the charger you’re using.

if it's the newest appletv you will need a cable with usb-c to connect to the remote and then usb-c or usb-a depending on what ac charger you are using in the other end.

usb-c cable connectors looks like this Amazon.com : usb-c cable