I have one too, 2013 I guess. I just use it as storage (samba-drive I guess) connected to my mini-computer (hp800) that runs hp800. I do occasional backups via rsync. It works. I also store some images etc. that I don't use there. But I only run a RAID, so I don't have the NAS backuped as well. I still have them in my old macbook backups. But not sure how to properly solve that dilemma of backing up a very large multiple TBs NAS, as I can't afford many more disks and another server to run just for that. If you have any a simple solution, I'm all ear :)
You can use Synology Hyper Backup (or any cloud backup program) and an AWS S3 compatible provider, such as Backblaze.
what would be an option to still do it locally? without sending it to the cloud? probably needs a good compression
You could have a big external USB drive and try a deduplicating backup software such as borg backup or restic.
borg is one that pops up all the time, maybe i need to look into that more deeply. I like rsync, but it's creating huge backups. thanks for the suggestions and help, much appreciated.