I think the problem is the trope of the setup she is in. When people see a reincarnator setup they are expecting revenge and a catharsis to all the abuse she went through before. They also expect that as an adult in a childs body she should be making some more sophisticated plans or be a bit mentally stronger than an average child. I totally agree that her being as sheltered and traumatized as she is it is unreasonable to expect her to suddenly be a strong op character with a lot of keen insight but she basically either acts scared or helpless the vast majority of the time which comes off as boring to a viewer that is used to this genre and expects to see her get revenge or do something different with her new life.
She just kind of comes off as a scared cinnamon roll without a mean bone in her body. which for this kind of fluff focused story is i think what they were going for but makes a lot of viewers annoyed that we are 33 chapters in and she has just been acting like a very passive baby lucking into a lot of help. We keep getting reminded she is supposed to be mentally 18 despite all the trauma so we get annoyed she acts like a child. We forget she was basically in a box her whole life so we wonder what the point of making her an adult even was if she isn't going to have any of the mentality of one.
Its just a weird writing choice that just confuses peoples expectations. I think they did it to just really hammer in how pitiful and abused she was without thinking about how its going to effect peoples assumptions of her. I agree with all your points I just think I understand why people are so frustrated with her character.
she's a young girl who was kept prisoner, abused, secluded from the world and horribly mistreated that was killed BURNED ALIVE in the same place she was kept locked up till she barely turned 18, you know what 18 is? a teenager not an adult 25 to 30-something woman with a full education, carreer, life experience or maturity who died in modern korea and was riencarnated, it's a traumatized child acting like what she is and even worse she's now back to her small and weak 7 year old body, stop expecting her to suddenly cure her ptsd and turn OP as fuck out of nowhere