Yuu can have growth by finally understanding/acknowledging that him not knowing what he wants is causing harm and that he needs to figure it out instead of rushing a decision even if that means he misses out on this opportunity b/c real feelings are at stake. Which is sorta what he's been doing, especially in this chapter where he acknowledges that letting Aya know he's not over her while also being in love w/ Hikari isn't exactly stellar behavior.
Yami ghosting him, and Hikari getting shitty about him having an ex-girlfriend that's none of her business isn't exactly stellar behaviour either. Particularly since Yuu at least had the courage to confess while Hikari chose to stew and sulk. None of the three characters come off looking good in this series.