You did it right. And it should work. At least it works in our test site (see screenshots).
We’ll roll out updated theme version later this day. It should fix the date format issue. And you should get a request to update the widget plugin. After the update, you’ll get the date format option for the widget.
Don’t forget to clear all caches after the update if you use some.
If the issue is still there provide us your URL. So we can better figure out the problem.
Best wishes, Owl Themes.