Ah, right, I almost forgot. Sure, he's smart and observant and able to figure shit out quickly from little information, but he's also a Main Character, meaning he's simultaneously denser than a fucking neutron star lmao
Seeing Dokja either notice or otherwise be made aware of tiny details like dirt on YJH's boots, know that YJH "vanishes" at a regular time each day, discover that this woman coincidentally appears every day at the same time, the constellations are reacting to her weirdly & in particular "a constellation who likes to genderbend" is getting extra involved (especially since he usually knows who each constellation actually is behind the screenname, too, meaning he knows what they're capable of & has extra insight as to why they'd care... even though it doesn't take a genius to put together "god who likes putting tits on things is participating" + "mystery woman appears whenever male character vanishes" = "some fuckery is afoot", imo), and yet he still doesn't make the connection... well, it's funny and kinda refreshing tbh, I expected him to immediately clock the situation & have some looney tunes chase/fight sequence with Yoo(ge tits) Joonghyuk due to his eternal tsun toward MC & the embarrassment of... whatever the fuck his internal logic is to be embarrassed about, lol. (I personally imagine he'd be more upset at the fact he needed help from a constellation [at all, but especially since it was for MC's sake] than just the fact he got genderbent, considering all of the dying and looping and changing shit he's forced to live through... I'd imagine that kind of life makes you care a bit less about your appearance in general when you've got the fate of the fuckin universe on your shoulders & the knowledge you can just reset at any time if something you genuinely can't handle crops up, tbh)