ALSO

Tell me if I'm wrong but I think it was mentioned or implied that Jaeyi did do swimming first, but when his brother started doing it he switched to Judo then later on just quit sports all together

this is what i was thinking i have this theory that (i’m just throwing some thoughts around but) he seems really familiar with swimming right, and also knows a place where ideum can learn swimming and said he convinced them to let him do so at his own pace showing familiarity not only with the place but the staff there as well? (and this is confined in the new chapter when the instructor says jaeyi called and begged him to take extra care of ideum) he also said before that it was really easy quitting judo cause he had no passion (and he did say that he feels those strong feelings feel fake but i think it goes deeper than that and we just caught a glimpse of it) ALSO in chapter 15 we see his friend saying “it’s not easy to give up on something you love” which contradicts jaeyis earlier thoughts of saying his heart was not in it about judo. also when he’s telling ideum about his brother and how his brother used his surgery to get what he wants it specifically shows him wearing swimming attire and the sentence as well is “even taking what belongs to others”. i did see someone say that maybe jaeyis brother stole jaeyis gf/bf at the time, which is a good theory but i think with the theme of swimming and everything else we know about jaeyi so far, could that have been referring to maybe a spot on the team or smth like that