In a way, I love the “yandere” archetype, but only in very rare cases. Usually, a yandere poses a threat only when the character is first introduced, and after that, they fade into the background. Often, as they take a backseat, the yandere’s craziness becomes just a comic relief, and the character is no longer taken seriously.
The only yandere who truly stays true to their archetype that I know is Yuno Gasai from Mirai Nikki. From start to finish, she’s a bloodthirsty, insane killer—not a villain for just one arc who later turns into a "gigs and shits" character.
What I mean is, if Sunbae were a true yandere, she wouldn’t be playing rival games with the other girls—she would just make a bloodbath. But most likely, the author will turn her into a “gigs and shits” character, like I mentioned above.
This is why I don’t want to see yandere characters in most works, especially in harem stories—because yandere in those stories are very unlikely to stay true to their archetype.