According to the Veeam Backup & Replication user guide12, WAN acceleration is a technology that optimizes data transfer to remote locations by performing deduplication and caching. It is specific for off-site backup copy jobs and replication jobs12.
Therefore, if you want to achieve the RPO of six hours with 500 GB of data and 50 Mbps of bandwidth, you should use backup copy jobs with WAN acceleration enabled. This will reduce the amount of data that needs to be transferred over the network and speed up the backup process12. The simplest configuration would be an immediate copy mode with WAN acceleration