What this means
Steel does not suggest a default login slug because predictable defaults turn into their own attack vector.
Recommended action
If another administrator knows the custom slug, use it and then disable or update the setting from the Hardening page.
If necessary, use controlled site access to inspect or reset the stored login-path settings so the default login route can be restored safely.
Rollback / Recovery
The intended rollback path is to disable the feature from the Hardening page when access is available.