Yeah, he really sort of stumbled into it all and kind of tries his best to be a good s/o to Hyunjin while also attempting to befriend the others. MinBin were easy, but he's much in the same boat as Changbin when it comes to Jisung - hence why they're good friends.
He's okay with Hyunjin's feelings for Jisung because Hyunjin treats Sung like a best friend and no more, and has never given the impression that he wanted to be more either. Besides, everyone in the little family of four seems a little more closely tied together than friends usually are, so Chan just sort of goes with the flow of them and tries his best to fit in. Hyunjin also ventures into his side of the social circle and tries his best to get to know him better, even if NFR didn't touch on it, so it's not like he's only giving and getting nothing in return.
Chan won't get tired of dealing with Hyunjin's friendgroup because he doesn't consider it 'dealing with' so much as just 'getting to know'. In the future, as Jisung mellows out and opens up more once he starts properly dating Felix and having had plenty therapy, things will also grow less tense because everyone else will be able to relax and stop being afraid of what might be wrong with him.

That aside, thank you so much for reading my little fics and asking me questions about them, I'm always happy to talk about my stories! 😊💕

Sweating profusely as I try to figure out whether I gaslit myself into thinking there is a Chan pov in NFR. Isn't there?

If you mean that in his pov there isn't much said about his thought process, that's honestly because he's not a super well-worked out character in that fic, I'll admit to it freely. But I think his pov is mainly that he loves Hyunjin, who he knows struggles with his feelings about Jisung, but that he likes what he and Hyunjin have and just wants to be there for and support his boyfriend. He's great friends with Changbin, too, but mainly the rest of his social life is outside of the flowershop and tattoo shop people I think. ^^

I write like I've been possessed by my characters. I get a vague story idea, or a specific scene, or a single line of dialogue, I start writing wherever the first word begins and then I just go.

I plot the absolutely zero anything ever. Most I have is some reminders of things I wrote earlier on in the story so I won't forget by the end or write inconsistencies. If I have a finished idea in my head, my brain does not think it's necessary to write it anymore so I have to keep myself in suspense as well until the very end! lmao

For the same reason, I also write in order. That is, in the order you guys get the fic when I post it. So if there's flashbacks or time's out of sorts, I write that as it appears as well, not chronologically. Only very, very occasionally will I skip maybe 3 ending paragraphs of a scene to write the next one when inspiration is so intense it bugs me, but you could literally read the story along as I write it.

I also edit very little at the end. I usually just go through for spelling, occasionally edit a line here or there, but it's always minor. My brain sort of ejaculates these words onto the doc and then I post that to ao3. Have fun with the mental image of that 😂😂😂😂