Apple Watch 7 & Magsafe Duo

The relevant Apple support doc is How to use MagSafe Duo Charger with your iPhone and Apple Watch - Apple Support. I have asked for it to be updated to mention iPhone 13 and Apple Watch fast charge, so just keep checking and hope it comes to the top of someone's to-do list soon!

The sport doc has now been updated on the Apple USA site, but it has not yet propagated to the international sites. Look for a mention of iPhone 13 in the header. Unfortunately it also says the Magsafe duo does not have the watch fast charge function.

https://support.apple.com/en-us/HT211925

At this stage we don't know. The Magsafe Duo documentation has not yet been updated for AW7 to mention the possibility either way.