Caroline, for example, might be more accepting as she is also a vampire. She could help Elena adjust to her new life. Damon, on the other hand, might be jealous or feel threatened that Stefan made Elena a vampire. It could change the power balance between the three of them.
Katherine turning Elena into a vampire changes her life in many ways. For one, Elena's diet changes. She has to resist the urge to feed on humans. Socially, she becomes an outcast among normal humans. Her perception of the world also changes. She starts to see the vampire society in a different light and has to find her place within it.
The story changes a lot. For one, Elena's place in the supernatural world shifts. She goes from being a target of vampires to being one of them. This means she's now part of the 'in - crowd' in a way. Her daily routine would be completely different. Instead of going to school during the day, she'd be prowling at night. And her relationships with the other characters would be redefined. Stefan and Damon would have to see her in a new light, and she might start to have a different understanding of Klaus too, not just as a threat but as someone who has given her a new kind of life.
One reason for Elena bashing in fanfiction could be that some fans prefer other characters over her. For example, they might be big fans of Bonnie or Caroline and feel that Elena gets too much attention in the show. So in fanfiction, they might downplay or 'bash' Elena to give more focus to their favorite characters.
Elena's final romantic partner in the Vampire Diaries novel is Damon. Their love story is full of ups and downs, but they overcome all odds to be together.
She could be terrified at first. After all, Klaus is a very powerful and dangerous vampire. But Elena is also a strong - willed character. So she might quickly gather her courage and start looking for ways to escape.
Damon's compulsion of Elena can completely change the trajectory of their relationship. It might make their relationship more passionate in some cases. For example, if he compels her to be more honest about her desires, it could lead to a more open and intense connection. However, it can also be a source of mistrust. If Elena discovers that Damon has compelled her without her knowledge, it could seriously damage their relationship and take a long time to repair.
Elena's character may become more cautious. For example, she might be more hesitant to trust new people. She could also develop a stronger will. After experiencing abuse, she might be determined not to let it break her and instead use it as fuel to become a better fighter. Maybe she starts training harder to protect herself from future harm.