Azure Backup support for up to 32 disks is now generally available
Published date: September 22, 2020
Azure Backup provides a simple, secure and cost-effective solution to back up your Azure Virtual Machines (VMs). Azure Backup now supports Azure Virtual Machines with up to 32 attached managed disks. Previously, the limit was 16 managed disks per VM. Support for backup of Azure VMs with unmanaged disks or classic VMs is up to 16 disks only.
Read the documentation.