Hi lsittler,
{{ClickElement}} is a Pre-configured variables, I somehow figured out some workaround for them.
You can refer my another post: How to refer a Pre-configured variable in Custom JavaScript
You can use
MatomoTagManager.dataLayer.get(“mtm.clickElement”)
or
MatomoTagManager.dataLayer.values[“mtm.clickElement”]
to get the values of these Pre-configured Variables.