I have never seen Yandere done this badly.
Normally Yandere is done a few different ways. In Future Diaries she was the MC's ally from the start and had charm. So even when she went off the deep end you were kinda rooting for her and felt bad for what happened to drive her into such insanity.
In a few others she's made the villain from the start but given enough authority, power, or intelligence to justify her not getting a quick end.
The most common use of Yandere gives her enough self control to not murder everyone and simply threaten or glare menacingly.
This? THis is just annoying. The girl is not smart or skilled enough to justify her hold over them. She stupidly killed someone as a pre schooler and brutally tortured another one instead of even once making the effort to win his heart properly. Then she "gets amnesia" although I still think she was faking it and reveals the truth on her own instead of using the fact they thought the old her was gone to get close to him. Even an idiot would know he's not the slightest bit happy and as a Yandere she should want to achieve genuine love not this paper thin act.
The thing that makes this worse with each chapter is that because the Yandere is not smart, strong, or anything the MC is turned into the ultimate wimp to prevent her downfall.