Not OP, but I have been using borg backup [1] against Hetzner Storage Box [2]

Borg backup is a good tool in my opinion and has everything that I need (deduplication, compression, mountable snapshot.

Hetzner Storage Box is nothing fancy but good enough for a backup and is sensibly cheaper for the alternatives (I pay about 10 eur/month for 5TB of storage)

Before that I was using s3cmd [3] to backup on a S3 bucket.

[1] https://www.borgbackup.org/

[2] https://s3tools.org/s3cmd

[3] https://s3tools.org/s3cmd

I cannot edit any longer, the second link was supposed to be

[2] https://www.hetzner.com/storage/storage-box/