Is it possible to manually test changes in AWS OpenSearch service blue/green deployment before switching over traffic?

I have read https://repost.aws/knowledge-center/opensearch-configuration-change and similar articles which have led me to believe that AWS OpenSearch "blue/green deployment" for cluster configuration changes works by adding new nodes to the cluster and then using native OpenSearch shard recovery process to relocate shards from the old to new nodes. During this process, query and ingest performance can be impacted and requests might be served by either the old or new nodes depending on status of the shard reallocation. This is also consistent with the cluster performance degradation I have typically seen during these events.

But the official documentation at https://docs.aws.amazon.com/opensearch-service/latest/developerguide/managedomains-configuration-changes.html seems to suggest that the green cluster is an entirely separate environment and can be tested independently before making a decision to switch over the traffic. In particular:

You can thoroughly test changes in the green environment. When ready, you can switch over the environments to promote the green environment to be the new production environment. The switchover typically takes under a minute with no data loss and no need for application changes.

Is this documentation accurate? My experience is that we have no control over when the switchover happens nor any opportunity to perform a test against the new nodes prior to that happening. Any further insight into how the OpenSearch blue/green deployments are implemented under the hood would also be much appreciated.