I use S3 API compatible object storage platforms for remote backup. E.g. BackBlaze B2. I wrote about my backup scripts for FreeNAS (jail that runs s3cmd to copy files to B2) here: https://www.shogan.co.uk/cloud-2/cheap-s3-cloud-backup-with-...
For Kuberenetes I use velero which can be configured with an S3 storage backend target: https://www.shogan.co.uk/kubernetes/kubernetes-backup-on-ras...