A problem with such products offered by GitHub is the fact that they're connected to a single repo. This is maybe suitable for monorepo situations or simple open-source libraries. However, teams work differently and need to manage backlogs across many repositories. The context is usually a team, project, etc. This requires pulling in multiple issues across repos into one backlog along with abilities to manage this backlog and calculate metrics.
I've seen some teams manage an 'issues' repository solely with tickets that are later linked to the individual repos' issues and PRs. It's quite a mess and GH does not seem to offer issue statistics and comprehensive query capabilities to manage issues.
Has anyone worked with an issue management system (not JIRA) that would be working across 100+ delivery teams and have decent integration with GH/GHE to show PR progress, issue status, releases, etc.? Any experience with FB's https://phacility.com/phabricator/ for example?