Yes.
You can use the diamond ring with Lexandra the telekinetic to get her alone without having sex with her. And it's who who gets blackmailed, by Zalgomma the magnificent.
GOG is still recovering from a server outage, so the DLC isn't available there yet, but it will be. I've now also just updated the GOG version to the latest version.
You can totally buy the DLC on itch and manually install it into your GOG Airships install by putting the "heroes" folder into the GOG Airships install folder.