Redundant S3 is easy-ish to selfhost, though, so that could actually be a decent way to setup reliable diskless workstations.
At that point you might as well run Ceph and give your diskless workstations a writable block device via RBD. The overhead of an S3 operation per file is quite high.
There are some easier solutions for just S3, like Minio, which I imagine is likely much easier to setup than Ceph (though ceph is not that hard with cephadm).
By the time you add the word "redundant" in the mix, nothing is really easy anymore.
His S3-compatible bucket was locally hosted, did not go over the internet.