okay, this response is gonna be LONG. i hope you'll have the patience to bear with me as i explain things, because while i get your concern about that, i certainly do not agree with how you perceive sunki. it is NOT unfair. and i will give real events why:

you said that ni-ki is the one who compliments sunoo, and asked about the other way around. there are actually many times when sunoo complimented ni-ki, out of those are the times he praised his dance. but since you might overlook that because everyone knows how ni-ki is great at dancing, i'll give some other examples.

during that sunjakewonki live, there's a part where they were talking about the comeback and ni-ki did the japanese narration. sunoo kept talking about how good it was, and when they were all talking, he waited until they finish to praise ni-ki again because according to him, “his (ni-ki's) japanese voice wasn't awkward at all” and when he heard it, it was so good like it was from an animation. he also praised him multiple times for being amazing during photoshoots because he does it quick and cool. another is when enhypen has a content doing the color analysis, and when the man asks “doesn't he (ni-ki) look good?” sunoo raised both his arms and genuinely said “wow” and clapped.

for the “paraan” or making the first move, i swear sunoo shows favoritism towards ni-ki. it's subtle, but you can see that and it's adorable. in one of the en-o'clock’s ep, even if they're all competing individually, sunoo keeps giving advice and helping ni-ki. another is when ni-ki almost spoiled something in a wv live, jakewon reacted, but sunoo defended him by saying that sometimes it's good LMAO. in one of their contents, the members talked about sunoo buying them beef. sunoo said, “i don't have time. if i do, of course i'd buy.” then he was asked, “for all the members?” and he answered, “no, for ni-ki!”

more: in the guessing game during their cola promotion (iirc) with sunoo doing the action where he irritatingly flicks his hair. other members gave their answers and hoonki happened to have the same one which is “when you don't like your hairstyle today” and sunoo said “i think ni-ki got it right?”. AND on one of the en-o'clock eps again, there's a part where someone did something funny sunoo got annoyed (jokingly) asking “who stuck it on the side?! who did it?” then ni-ki turns himself in, saying it's him. then suddenly, sunoo says, “amazing” with a smile on his face 😭

you don't have to mention that it's a "maknae thing" because i'm pretty sure sunoo has said multiple times that he thinks he's younger than ni-ki for being spoiled by him. let's also not forget that ni-ki is the only one to be part of “sunoo's emotions” post!!!

this is gonna be the last paragraph. i just want to say again that whenever you see sunki glancing at each other, pay attention to how they do it because that's where it lies. it may differ in appearance, but not in intensity nor intention. i hope you were satisfied with me dropping facts with this, there are so much more but it won't fit in here.