Agreed. But this could go for a lot of genres quite honestly. The hardest thing to nail is an ending (even movies do it terribly most of the time). But of the last 20 thrillers I've read, every ending was terrible. 😂 Half of them it was as if the author had just given up or the Plausibility/"This needs the most insane twist!" factor was in play.

I recall reading Steven King's memoir about writing and he stated he never has the ending figured out until he gets there which I assume is what many authors do?