Kopia

A fast, encrypted backup tool that creates deduplicated snapshots of files and directories and stores them in a repository you choose, from local disks to S3, B2, SFTP and other cloud backends. Snapshots are always incremental, so unchanged files are uploaded once, and policies control scheduling, compression and how many hourly, daily, weekly, monthly and yearly versions are kept.

It ships both a command line and a web interface, and that interface lets you mount a snapshot as a drive to browse it and pull individual files back.

Running it on your own infrastructure keeps the repository and its password inside your perimeter, costs nothing per host, and lets you script, test and monitor restores the same way you would any other service.