How to export data in cold storage to S3?

Dear all,
I am looking for a way to directly backup my data in cold storage in AOS to S3, is there a way to do this?
I have checked out the document in AWS, here are some questions:
When i do manually snapshot for AOS fllow this one:Creating index snapshots in Amazon OpenSearch Service - Amazon OpenSearch Service and Take and restore snapshots - OpenSearch documentation
Is the snapshot could select indices in cold storage, or any restrictions ? Because i saw the document in AWS cold-snapshot also said that i have to contact support to restore cold indexes from an automated snapshot, so what about manually snapshot, do i have to move the cold storagr back to ultrawarm/warm first?