“Luka is poorly written because he has no flaws”
“They will have to give Luka some flaws otherwise it won’t be believable when Marinette breaks up with him”
Many parts of the show including the side characters/secondary love interests are poorly written, period, Luka ain’t special in that regard.
It’s hard to give a character you want people to like flaws when they’re only on screen for a few minutes at a time.
They don’t need to give Luka flaws to break them up, it’s enough that he’s Not Adrien. Luka looks at Marinette at any point and says “you’re still in love with Adrien, go be happy” and then she’d give him a weepy cheek kiss and go racing off after Adrien a la Frozer. Look me in the eye and tell me that would be unbelievable in the context of the show so far, even after Miracle Queen.
They are not together, unless “play me a song” is some hip new lingo for “be my boyfriend” so there doesn’t have to be some big dramatic breakup?
If you’re trying to make a foil for your male lead and everyone is like “he’s so perfect” then dude maybe that secondary character isn’t the one you should be rethinking? I mean I would argue that Luka has all of Adrien/Chat’s good qualities but none of his flaws? (He’s romantic and protective without being jealous and pushy, he’s perceptive where Adrien is dense) Could it be that maybe The Folks In Charge don’t actually see Adrien as all that flawed? That maybe they think Luka’s gentle nature is enough of a flaw in itself? That maybe they think maybe given the choice of a jealous (passionate) pushy (persistent) guy or a gentle (weak) respectful (boring) guy, women would universally choose the former?
Don’t get mad, write (or read!) fanfic. It’s actually not that hard to extrapolate some potential flaws from what’s been shown on screen. I can think of three right off the top of my head that haven’t necessarily been shown but could be believable.
No one actually “needs” to acknowledge that he (or any other character) is poorly written if they don’t want to? Let people like what they like? You don’t know what version they’re seeing in their heads?