The complexity with S3 or Backblaze B2 is the granular pricing for various operations on the service. It’s difficult to optimize costs compared to a fixed “$X per GB” pricing that’s easier for people to understand and forecast expenses a bit more easily. Other than that, rsync.net provides the same pricing for different days center locations, which means there is some subsidization going on.

There are services like rsync.net that support borg at a lower price. Borgbase is one of them. I haven’t used either of these.

I treat zfs far more reliable than restic which is still rough around the edges the last time I tried a few years ago.

Run rsync to the target and forget is quite easy, though I admit rsync.net's deal is getting worse these days posing minimum usages here and there.