Here is a tool that might do what you want;
It does leave you open to someone accessing the data on the remote system while the dataset(s)/pool is unlocked. Probably low risk since you’ve presumably got strong passwords on accounts and not running services like SMB, but still not as secure as having no way at all of decrypting the data on the destination.
If the source were encrypted, there are zfs switches you could use on the command line to replicate the raw encrypted data;
https://forums.truenas.com/t/what-is-encryption-for-destination-in-replication-task-wizard/31133/3
But this would also likely negate an incremental type backup strategy.
You could also look at a “Cloud Sync” task instead of ZFS replication. You’d need to run some sort of cloud service on the target, perhaps Minio;
But Cloud Sync tasks do allow you to encrypt the data locally and send it out where the destination has no knowledge of the key.