Do you use WebUI.delay(n) with fixed value of n? That makes your test case run slow due to unnecessarily long delays. If yes, you should avoid it. You should prefer WebUI.waitForXXXX() keywords.
Do you find vast volume of “StepExecution” logs in the log viewer? If yes, you should disable it.
Does your Test Case script has for or while loops, or functions which are called frequently, then you should move the script out of Test Case and bring it into Keywords. In general, a Test Case script runs slower than a Keyword because Katalon Studio takes verbose execution logs of Test Cases but it doesn’t log Keywords.