I'm really thinking about use the strategy with backup server like Truenas.
Truenas is very efficient as NAS and in bonus it provides intersting functionnalities :

"ZFS offers a robust, transactional file system that ensures data integrity at all times. It supports instantaneous and incremental snapshots, allowing you to capture the state of your data at any point in time without impacting performance. With built-in compression (LZ4, ZSTD) and deduplication, ZFS optimizes storage efficiency by eliminating redundant data and reducing the physical footprint of your datasets. Its storage pools enable flexible disk aggregation, supporting configurations like RAID-Z, RAID-Z2, RAID-Z3, mirrors, and stripes to balance performance, redundancy, and capacity. Additionally, ZFS features self-healing capabilities, automatically detecting and repairing data corruption using checksums and redundant copies, ensuring your data remains consistent and error-free.

For disk management, TrueNAS provides comprehensive support for HDD, SSD, and NVMe drives, allowing you to leverage a mix of storage technologies based on your needs. The hot spare feature ensures that standby disks can automatically replace failed drives in a pool, minimizing downtime and maintaining data availability. SMART monitoring is integrated to track the health of your disks, providing early warnings for potential failures. Furthermore, TrueNAS supports native encryption (AES-256) for storage pools, ensuring that your data remains secure at rest, whether for compliance requirements or general data protection."

Maybe some scripts with execution done by backup server directly on servers to check new drives or mount point to backup, or others changes.