Problem Statement

Roadmap only displays 3k of issues/300 epics at the moment

Suggestion

Increase issue limits for Roadmap view

Update from Atlassian 2nd June 2022

Thank you all for your valued feedback. 

To set some context - The basic roadmaps feature on Jira Software Cloud is targeted at a single software team with one project per roadmap. Currently, this view only works with issues from the backlog associated with one project. https://support.atlassian.com/jira-software-cloud/docs/set-up-the-roadmap/

We have now increased the issue limits on the Basic Roadmap view on Jira Software Cloud for all editions. There is a limit of 5000 issues, and 500 epics which are "Open issues + Completed issues up to 12 months ago". This is the same limit for the board and backlog. If you see that your project is reaching above this limit, you can try to close epics and issues no longer required within that project. 

Cross-project planning with multiple teams is only possible in Advanced Roadmaps which is targeted at "teams of teams"/software organization level planning, which is included with Jira Software Premium and Enterprise subscriptions. This can be accessed via the "Plan" tab on the top navigation if you are on the premium.
More here on how to set up your first plan: https://youtu.be/xJ-RmFwEVjM .

Thanks again for your feedback and time spent articulating the needs of your team. We really do value it.

Regards,

Rathesh Richards, Product Manager.