Just follow the author's official account and arts. It's very rare that an author promotes, inflates and 'promise' a ship so hard and explicitly just to deliver a heart break in the end.
The author also already said in a Q&A that Nakyum and Seungho would be happy 'their own way'. Some people don't want to believe this means to be together but I think this is just the author not wanting to be too matter of fact. Who goes ahead and just say; Yes, they will be happily married?
Somebody also posted here a great list of all the flags and tropes that POTN has that shows this is a classic Yaoi formula where Seungho and Nakyum change for each other and become a couple. They both are monogamous (Seungho becomes one after falling for Nakyum). They both have influence on how the other thinks, they both will end up making sacrifices for the other along the story. Their union will be threatened by external people, both with bad and good intentions, etc, etc.
If you need spoilers, I really think the best is to see the blatant selling of the ship that is the author's official art, especially the ones where Nakyum and Seungho are happy. Unfortunately it seems some official art is not equally distributed by country. I particularly like one where Nakyum is sitting with his head on Seungho's lap and Seungho is playfully biting this finger. Another one is Seungho carring Nakyum in the snow. I have a hard time believing this author would do the know bait and switch where she sells and promotes this kind of happiness and pulls the rug at the end.
They will be happy together. The drama though will be intense.
with all this fckn drama, seungho & nakyum better be the endgame. i know some of y'all gon think seungho is toxic as hell but IMO atleast they deserve a freakin chance together where seungho is at his best behavior, like they need a GOOD VANILLA sex, no force, no rape. if they're not gonna end up together please tell me. someone spoil me if y'all alrdy know abt it please