Once the whole isekai event occurs, the story immediately starts trying to heap as much trauma as they can on the protagonist, they end up encountering an injured person while making their way to the nearest town, since the MC is a healing class they help them out, and try to give them some advice once they see that said person seems to be in a difficult situation. Normal enough interaction, right? Except, the person who the MC helped sells them out to a bandit group which results in the MC being captured and sexually assaulted, barely being rescued by their aforementioned friend and sibling before they reached the "point of no return". This event reignites their old trauma and amplifies it to the point that the MC cannot accept the events that occurred, so they rationalize the event to themself as if it didn't happen to them, but rather their in game character, which results in the MC developing a split-personality. Normally, this would be where the story takes a large pause for maybe like a month or so, give the MC time to recover, however not even a week later the spirits (?) of the bandit group, somehow fuse together to become some sort of dark tentacle/tendril monster, and I'm sure you can guess where this is going. Series of events happens, MC almost gets completely violated again, gets saved by sibling, sibling goes back to defeat monster, but doesn't have enough power to defeat it. Now that you're up to speed, the MC worries that their sibling will die, and realizes that since they themself are incompatible with their current body, they don't have enough strength to save their sibling. So they accept their split-personality (the game character), leading to what is basically a fusion of the MC's personalities (although it seems that the only thing retained from the original personality is the memories) which gives them a power boost and lets them save the day. It's a decent, albeit somewhat cliché character arc. However, I really think that the author should have drawn it out more, I understand that drawing things out for too long is annoying and can decrease the quality of a story, but the MC basically goes from college age/graduate boy to 13 year old girl in terms of personality in the span of a week.

nearly r*ped by bandits, before being rescued.

in large way, in a climatic moment