Trident dynamic provisioning and FSx...

You can consider checking below AWS blogs for persistent storage on Amazon EKS as they have example file system created with "persistentVolumeReclaimPolicy" set to 'Retain'

• https://aws.amazon.com/blogs/storage/persistent-storage-for-kubernetes/
• https://aws.amazon.com/blogs/containers/using-amazon-fsx-for-windows-file-server-as-persistent-storage-on-amazon-eks/

Sharing one example snippet

#pv.yaml
---
apiVersion: v1
kind: PersistentVolume
metadata:
  name: efs-pv
spec:
  capacity:
    storage: 5Gi
  volumeMode: Filesystem
  accessModes:
    - ReadWriteOnce
  storageClassName: ""
  persistentVolumeReclaimPolicy: Retain
  csi:
    driver: efs.csi.aws.com
    volumeHandle: fs-073d77123471b2917