One of the interesting capabilities within Jira Product Discovery is the timeline view of a roadmap. However, the 'Ideas' structure is completely flat, it doesn't seem possible to group multiple ideas into a 'Release' that would display on the timeline.
I appreciate the concept of Releases exists in Jira, but Jira Product Discovery is being promoted as the tool where you can share your roadmap with stakeholders (especially non-technical ones) and having a view of ideas rolled up into a release would be very important to present a clear picture of the roadmap.