Unfortunately, it’s not possible from the group-level. You could maybe open an issue for it here: Issues · GitLab.org / GitLab · GitLab so that a Gitlab Dev could potentially include it for the future.
As an aside, you could use the Gitlab API to achieve what you wanted:
curl -s --header "PRIVATE-TOKEN: your-access-token-here" "https://gitlab.example.com/api/v4/groups/yourgroup/issues?state=opened"
the output is in JSON format. You could then potentially turn this into CSV format. Replace
gitlab.example.com with your servername/domainname
yourgroup from the above and it’ll do what you need. This will default to 20 per page. so you can add to the end of the URL:
curl -s --header "PRIVATE-TOKEN: your-access-token-here" "https://gitlab.example.com/api/v4/groups/yourgroup/issues?state=opened&per_page=100"
to have 100 issues per page. See pagination docs, to work with this: API Docs | GitLab
For issues, you can change state=opened to something else: Issues API | GitLab if you want to find other states for issues, such as closed, etc.