How to implement following requirement: Execute one operation when some system internal keywords execute in test case?

Have a look at the following:

My trick shows you how to modify the behavior of Katalon builtin keywords on the fly.

For example, when my test case called WebUI.setText(TestObject, String) keyword, not only the text is set into the element but the element is highlighted. See the following demonstration video:

https://kazurayam.github.io/HighlightingElementByTestObjectInEachAndEveryStep/