People having trouble getting this configured is a common issue for self-hosting Forgejo Runner. As a Forgejo contributor, I'm currently polishing up new documentation to try to support people with configuring this; here's the draft page: https://forgejo.codeberg.page/@docs_pull_1421/docs/next/admi...

(Should live at https://forgejo.org/docs/v12.0/admin/actions/docker-access/ once it is finished up, if anyone runs into the comment after the draft is gone.)