S3DirectBatchHandler cannot be used solely with a AWS ID and secret. Is use of use IAM instance roles optional? If it is optional, the batch handler needs to be able to start without a roleArn definition. See attached server.log with entry
See also attached showconf.txt with nuxeo.s3storage.* properties.
Prior to 10.10 this class could get temp credentials rather than assumeRole https://github.com/nuxeo/nuxeo/blob/9.10/addons/nuxeo-core-binarymanager-cloud/nuxeo-core-binarymanager-s3/src/main/java/org/nuxeo/ecm/core/storage/sql/S3DirectBatchHandler.java#L193
If IAM instance roles are optional, it should be possible to either get temp creds or assume role.