i guess Ian could become a person like this. the problem though is that there would need to be a explanation as to how, as now he isn't anything like that. i mean, one thing i really really like about Ian is how forthcoming he is with lies that could deteriorate. "Minerva doesn't want me to meet Ward? fuck that, i'll show up anyway" "Axel is Lena's ex? better tell him straight away!" "shit, i couldn't deny Holly! better tell Lena i fucked up!". that does mean he has the attitude and the confidence to get whatever he wants, but he lacks any drive to manipulate anyone for just his own gain.
a scenario that i can think of that could jump-start him becoming a chad player, actually could include a cuck scenario a lot of people seem to want here:
for example Ian could find out in a gruesome way that Lena fucks Jeremy (like he is unbeknownst to Lena and Jeremy at the club and sees them go out into an alley. for cuck route he stays and watch). he gets reminded of Gillian and starts to not only resent Lena, but also Jeremy because he trusted him when he said he loved Lena. now he has to face Jeremy in the tournament and uses his rage to win the match. he realizes he felt good after that and decides to outplay the "player" Jeremy, by trying to get every girl Jeremy wants. this is also a good introduction for Ian x Ivy scenes.
the only problem i see with my scenario is what should happen, if your Lena isn't interested in Jeremy, as then it could become a little hard to give Ian the drive to be manipulative and would lock everyone out on that path, who don't want Lena to go after Jeremy.