I Suspect Restic will already support C14's standard class since it's S3 compatible, but it would be nice if it could also support the Glacier Glass, I presume indexes.etc would need to be kept at standard, but it would be nice if the data could be stored with the Glacier Class, at least older data.

https://www.scaleway.com/en/docs/object-storage-glacier/

Unlike AWS there's no retrieval fees, just a delay + whatever storage costs would be incurred for keeping the data in the standard tier for as long as it needs to be there (to access it)