is it possible for defects in testops to integrate with redmine? or only integrate with Jira
Whatever have a certain API can be integrated with Katalon.
You can develop a test listener to create/update redmine issues based on the test case status, by sending RESTfull calls.
see for reference:
https://www.redmine.org/projects/redmine/wiki/rest_api
Yes, Katalon integrate with RedMine, but in TestOps will appear the defect?