Meant to mention this earlier: Gitlab self-hosted actually has a built-in importer to import projects from Gitlab.com - including issues.
It's mostly worked reliably in my experience (it's only failed to import one project across the various times I've used it, and I didn't bother debugging because for that import we really only needed the git data).
It's mostly worked reliably in my experience (it's only failed to import one project across the various times I've used it, and I didn't bother debugging because for that import we really only needed the git data).