If that bandwidth is shared between site to site and WAN then WAN accelerator would make sense if you’re planning on uploading to cloud-based object storage too.
Currently we are not so confident in our Backup System so it's time to do it from scratch but do it in a propper way.
To start at the beginning, you should aim to do the 3-2-1-1-0 rule. Whilst it’s called a rule, I prefer to call it the minimum amount of effort you should invest in your backups.
3 Copies of data, this can include your production, but it’s better when you don’t. If you’re going to have a production copy, a local backup, a backup copy in another country, and backup to cloud, then that’s fantastic. You’re certainly meeting & exceeding the 3 copies of data. If you want to stop doing the site to site backup copy and instead swap that with cloud, you're still meeting this criteria.
2 different media. This can mean different things to different people, for some it’s using different file systems between backups (ReFS/NTFS/XFS etc), for others, it’s a vendor hardware break, so you can’t use the same RAID controller/manufacturer for all of your backups to prevent a firmware-level issue, but the (In my opinion) best classification of this, is different media types. Such as block-based storage, object-based storage, and tape. These different architectures can help preventing issues with bad code in one type of hardware, or the integration code within Veeam. The weakness I see here in your current setup is using the same Synology NAS’ everywhere.
1 backup copy stored offsite. You’re meeting this and evacuating it to well out of the country which is great, and offsite/cloud object storage would help too.
1 immutable/offline copy. This is where you’re probably the weakest, you mentioned an airgapped NAS, but ideally some more information would be useful here to determine how effective the airgap is. immutable object storage can help dramatically with this, and I personally would try to have a backup copy that exists on storage outside of you/your team’s control, meaning that you’ve got backups on storage that nobody who compromises your environment could then also delete, as they’d have to compromise another environment hosting that data.
0 verification errors. This refers to using technology such as SureBackup to spin up your backups and confirm they’re all happy & healthy, in advance of needing them for DR.
With that all out of the way, this is an example template of how your backup solution should aim to look. You’re doing well, and hopefully the feedback I’ve provided above is constructive. If you want to provide further details on what you want to achieve then I’m sure collectively as a community we can help 😊
