Just sharing; it might seem odd, Typinator functionality is replicated by KM but I don’t think KM can be scripted to create new macros or check for their presence—and for me Typinator does text expansion a little better—so I thought one or two or you might find it useful.
The link to my github below has an applesscript script which checks is the contents of the clipboard contains a unicode character or unicode decimal number; if it does, checks if there is an expansion for it already; if not pops up a dialog asking for an abbreviation.
I add it to this forum as I use KM’s clipboard trigger to launch it. The checks inside the script mean I don’t see many false positive dialogs pop up.
You can find it here.