Sounds like y’all need to import the apache commons library and use:
https://commons.apache.org/proper/commons-lang/apidocs/org/apache/commons/lang3/time/StopWatch.html
Beyond that, I have to ask, why would you do performance testing with Katalon (which I would argue is purely a functional testing tool)? There are plenty of other open-source tools out there that will offer much better accuracy and functionality. Namely: https://jmeter.apache.org/