Glacier doesn’t allow immediate read access to the objects. As such, Duplicati fails when it tries testing the files. I personally advise against using archive tier storage. (You can get hot storage at about the same cost as Glacier from other cloud providers such as Backblaze B2 or Wasabi.) Google does have an archive tier that allows for near immediate access, so that’s another option.
If you really, really want to use Glacier, then you should set these options:
--no-auto-compact = true
--no-backend-verification = true
These should get your backups to run without error.
But note that I don’t know how restores even work, since object availability on archive tier storage is measured in hours. I imagine Duplicati will fail on restores unless you move the objects to a higher tier. You should definitely test this thoroughly.