Export opensearch dashboard config index policies index patterns

Im trying to save current configured dashboard config to re-import

this works
curl -XGET http://localhost:5601/api/status -u kibanaserver:‘mypass’

trying to export all dashboard config to re-import on new installs as template
curl -X POST http://localhost:5601/api/saved_objects/_export -H ‘osd-xsrf: true’ -H ‘Content-Type: application/ndjson’ -d ‘{ “type”: “index-pattern”}’ -u kibanaserver:‘mypass’
{“statusCode”:415,“error”:“Unsupported Media Type”,“message”:“Unsupported Media Type”}

I see reference to import here

Im seeing export import in gui under stack management/saved objects in 2.x version
was looking for curl so can use as templates