Does such a thing even exist? I couldn't find it. It seems such a logical thing. Charging puck + bring your own cable (iPad's, MacBook's...) and charger.
This, basically. But not with a ton of negative reviews on Amazon.
I've always considered devices with non-removable cables (MagSafe chargers, Homepod...) inferior. I know that with Apple's puck most of the electronics is in the USB-C connector (to minimize heating of the watch). Still this seems like a much better solution for travelling and making USB-C really universal.
I think the Apple Watch Magnetic Charging Dock is the closest you're going to get. It has a lighting in port on it, and it's bigger than just the puck, but it works great & allows you to use your iPad (as long as it's not a USB-c one)/iPhone cable to charge the watch as well. I have two & they work great