Restic supports a similar feature set to Borg (open source, locally encrypted backups, content-addressed snapshots instead separate incremental+full backups, etc) but also works with dumb file hosts (S3, Backblaze B2, a local drive, etc).
Indeed, and it's a powerful combination. With "autorestic" as a bit of a front end, I have backups going to a local SSD, home NAS, and Backblaze B2. My B2 storage is under 200 GB so far, but has also cost basically nothing. For that, I have at least some chance of getting data back if the house burns down.