Wow, Kopia looks pretty interesting. I first thought that it's a fork of Restic, but it appears to be independent. It has all the features that are key to me: encrypted, deduplicated, works on object storage, can mount the backup as a filesystem.

On one hand, on may think that three programs with very similar approach and features is a waste of resource. On the other hand, this is what refinement of the idea looks like: each project improves over previous attempts.