@Emil They mean "tap to edit" doesn't seem to work in the iOS app, currently.
The same thing happens on my own iPhone: When trying to try to modify any Matter devices, tapping on "tap to edit" does nothing.
EDIT: Just discovered that editing Matter devices does work, but only when you access them from the "Providers" page within the hub settings; trying via the "modify" section when choosing a button action does not work. @sam, perhaps you could try from the "Providers" page?