Use PUT for the repository file (it already exists on the fork), create the MR on the fork with target_project_id (the create endpoint ignores source_project_id), and reuse an open MR instead of deleting and recreating the branch. Drop the unused --branch/--title flags and the redundant workflow concurrency/defaults.
The fdroiddata recipe is now kept in tools/fdroid/ as the source of truth. tools/fdroid-submit.nu pushes it to the fork and opens the merge request via the GitLab API, so no fdroiddata clone or manual web editing is needed. Also runnable from a Forgejo Actions workflow_dispatch.