Yes.
Stick to Junit!
Why am I saying this?
For few reasons …
Katalon use own implementations and concept regarding what a test-case, a test-suite means.
If the user need is migrate from Junit, TestNG or whatever other framework then some manual work is needed.
TestCases, Suites and so on must be re-written, simply importing the code and expect magic won’t work.
You have to ‘import’ the code by manually copy paste and addapt it as katalon testcases.
There was a brief video-tutorial somewhwere on how this may be achieved and steps involved, I cannot find it anymore.
Feel free to search for it.
The reason for using Junit, TestNG or whatever other framework with Katalon may have the only sense if you would like to do some unittests for your own develloped classes / keywords and eventually validate those without using KRE.
This has been briefly debated in:
… and the efforts made by @kazurayam are, for my eyes, more or less for same reasons.
Hope this helps!