If you need instant replication then Syncthing is probably your best bet but don't forget to disable the relaying function

They have been sued out of existence by patent trolls ☹️

I only encrypt the data using LUKS and I have a password stored in Google Secrets Manager. I have a script that runs as a systemd service, goes fetch the password and unlocks the volume. If the drive is somehow stolen, I just revoke the key and the data is unreadable.