You've already summarized everything, but it's not just that that irritates me, it's the fact that I can't have any empathy for the antagonist and the unrealistic script that makes this shit worse doesn't even help in the sex scenes, I can't like it because of that shit is in the scene I have nothing against NTR in fact some are even interesting. like thisThe plot is contrived and unrealistic, yes.
The plot can be irritating to some, yes, but this is a work of fiction aimed to fans of NTR. Even then, not every person will like it.
Luca has a reason (personal, utterly petty and psychopatic/sociopathic) to torment Harry. Whether it's a good one depends on how you see it.
As for Harry, his naivete, passiveness and habit to not think about/ignore certain matters are part of the reason the plot advances. And the flaws he has to overcome to get the Good ending.
https://f95zone.to/threads/ntrd-by-clumsiness-v0-7-0-hangover-cat.142006/unread