It depends. If the portrayal of the yandere girlfriend is done in an interesting and nuanced way, it could be appealing. But if it's overly stereotypical or one-dimensional, then no.
A gift from her in a yandere manga can have multiple meanings. It could be a sign of the yandere's obsessive love, an attempt to control the situation, or a way to create drama and tension in the story. Sometimes, it might even be a red herring to mislead the reader.
A great male yandere story is 'Diabolik Lovers'. The male characters in this story often exhibit yandere - like traits, especially when it comes to their relationships with the female lead. They are overly possessive and their actions are sometimes extreme in their desire to keep the girl close to them. Also, in some darker versions of fairytale retellings, there are male characters who turn into yanderes. For instance, in some reimagined versions of 'Beauty and the Beast', the Beast can show yandere - like tendencies towards Belle in terms of his possessiveness and jealousy.
Well, such a girl is often obsessive and possessive. She might go to extreme lengths to keep the person she likes close to her, sometimes even using violence or threats.
Well, 'Nana' is often touted as a top romance manga. It delves deep into the emotions and relationships of the characters. The art style is also captivating.