Answer
If your middle-tier setup used the Advanced/Manual installation mode, check whether the installer's dedicated Storage resource step was actually run alongside the other usual manual steps (like KEY and KUBERNETES) — a missed main.ps1 -resource 'STORAGE' step (which installs the underlying IFS storage Helm chart and its own namespace/pods) is a common cause of the file-storage pod hanging in Init state despite an otherwise-successful installer run; running that step and confirming the resulting storage namespace and pods come up correctly resolves it.