She's still physically stong af. So idk what you're complaining about her being fragile. Maybe you're referring to the mentality part/psychological part. Which everyone that commented above me stated already, it's a trauma. This is not a villainess revenge themed story. It's just a story about her reincarnating/traveling back in time. And her setting her life on the right track and not letting any of her friends die and her not regretting any shit. Trying her best to be a better person and preventing shit from happening.
I think things related to the black knight commander (like a behind the scene political/rebel/ any weird dark master plans... idk) will be revealed for later like some investigating shit, so yea...
And we're still at the start of the story so let's not judge it just yet. And if I'm wrong and you're right. Then advance apologies.
This is an interesting story, but the MC devolved into a fragile person rather than a badass knight. I am not too keen on reading some number of chapters just to get back to being a strong character. I hope it is not a situation where she will be dependent on the ML rather than standing up for herself.