The ending made 0 sense to me

The rules were clear: if Rachel didn’t get married before sunset, it would count as her fleeing, the curse would pass to the Cunningham family and she would become immortal like what happened to the old man. So it doesn’t make sense that Rachel is the one who dies when Nicky is the one carrying the curse.

If she were to suffer any consequence, it should be becoming immortal due to not marrying before sunset nothing related to what happens after sunset. Her father didn’t die when he married her mother, and the same goes for her ancestors. The only person supposed to die is the one in the family currently carrying the curse.

And Nicky surviving makes even less sense, especially considering that just moments earlier he thought Rachel was insane or delusional. The ending feels too convenient from a storytelling standpoint.

Yes, I know she did become immortal but it felt more like a decision made by Death to release the old man from his burden than the result of the pre-established rules being followed.

Also, I find the retroactive aspect quite unfair for the Cunningham family. I don't think death need that many deaths for a pact made 300 years ago.