We have Jira and ServiceNow and I wish we just moved everything into Jira rather than dealing with two systems and syncing tickets between them.
That's sounds horrible !
If I had to sync tickets I would also wish for a Jira only workplace as I mostly do projects that require development and planning but I am almost sure that the peoples who mostly do customers and employees support would have the opposite opinion.
Maybe they will eventually drop JIRA for the ServiceNow agile development module but they (the deployment team that I'm not part of) have many modules to deploy before evaluating that.