Explanation
https://helpcenter.veeam.com/archive/backup/110/vsphere/instant_recovery.html

Reference: https://helpcenter.veeam.com/docs/backup/vsphere/replication.html?ver=100

Veeam does not support immutability on a NAS. There are only 2 ways to enable immutable backups.
1 - Setup a Linux Hardened Repository.
2 - Use AWS/Azure Cloud storage with immutability enabled.

To avoid running out of space when moving backups to a new repository, the "Move backup..." function in Veeam Backup & Replication should be used. This function allows you to relocate backup files to a new repository without duplicating data, which can save space. Unlike a simple copy action, the move function ensures that the backup chain remains intact and does not require additional space for a copy of the backups during the transfer. When the move is initiated, Veeam will also automatically update the configuration to point to the new backup location, thus preventing any disruptions in the backup chain.

In a scenario where a Veeam engineer needs to manage backup file transfers between two sites without impacting bandwidth during business hours, the most appropriate feature to configure in the backup copy job is D: Backup Copy Window. The Backup Copy Window setting in Veeam Backup & Replication allows for specifying the time frame during which the backup copy job is allowed to transfer data. By configuring this window to exclude business hours, the engineer can ensure that the backup copy job transfers data only during off-peak hours, thereby avoiding additional strain on the WAN connection when it is most needed for business operations. This approach provides the flexibility to balance the need for offsite backups with the practical bandwidth considerations of a busy WAN connection, ensuring that backup activities do not interfere with critical business functions.