Ah gotcha, I haven't done full restore of my main dataset.
I've only verified with a smaller test dataset to validate the workflow on s3 deep archive (retrieval is $0.02/GB). I've done full backup/restore with the zfs send/gpg/recv workflow successfully (to a non aws s3 destination), and used s3 for quite a long time for work and personal without issue, so personally I have high confidence in the entire workflow.
I've only verified with a smaller test dataset to validate the workflow on s3 deep archive (retrieval is $0.02/GB). I've done full backup/restore with the zfs send/gpg/recv workflow successfully (to a non aws s3 destination), and used s3 for quite a long time for work and personal without issue, so personally I have high confidence in the entire workflow.