Like gryffinpuff said, first comes up the issue of the original soul's memories. In the chapters two and three, the MC mentions she saw the memories, and thus concluded she reincarnated. But then later, she suddenly says she didn't recall anything when she woke up? And that she needs to investigate this new body's identity?

Ok....I was willing to get past that, since it's not too major, but then:

One of the nation's princes appears in her room (she's staying at another prince's residence) and she basically says when she realizes he looks sickly: "Ah, you're here because of my medical skills, right?"

But the problem is.... she hasn't had the chance to show her medical skills yet! At least not to anyone else that isn't us, the readers, so why is she saying that?

I think gryffinpuff worded it incorrectly - it's not that the readers found her medical skills to be out of the blue, she managed to treat her own injuries and is clearly skilled enough to create poisons w/ some herbs she bought. The problem is her suddenly saying that when she has never met this prince nor been in any situation where she's shown miraculous medical skills to the public - and it would've had to be a tremendous and significant show, because this is a prince! Otherwise, why would he go to her, who at this point is only known to be a "servant girl", when he can get much better doctors for himself?

Again, this isn't anything major either, but it is something harder to ignore. And it makes me feel as if this might happen a lot later in the future, where suddenly things pop up w/ no logical basis.

First, The Reincarnated Female Lead; The author constantly reiterates she is trying to hide her powers to keep her enemies from knowing she has reincarnated. She reincarnates as a s*ave in a coliseum, where she has to battle beasts. She is there about a week, and then she is bought by some mysterious Prince (Prince #1) and placed in a mansion where suddenly she has servants she can order around, the run of the mansion, expensive clothes and she treats all this as normal despite never meeting the Prince who has bought her there.

Then the night after arriving in the mansion, she watches an assassin/thief get caught sneaking inside the mansion get chased away by guards. Sooo when she returns to her room, she finds a strange man who has sneaked into her room waiting for her. She has no worries about assassins (despite just watching one being chased away), she has no worries about her enemies discovering her (despite how she constantly goes on about hiding from them to recover her powers), she just nonchalantly tells him (with no reason for her knowing this), that he must be Prince #2, she then volunteers to diagnose him with her super secret powers then volunteers to cure him. WTF!!! Where's your motivation to hide your powers until you have fully recovered you idiot? And why would you offer this to a dude you have never met before who sneaked into your room in THE MIDDLE OF THE NIGHT, right after you saw an assassin chased away?

And from the Prince's POV; He sneaks into her bedroom, in the middle of the night (and not just sneaked into her room, sneaked into his brother's mansion) because he is hoping she can cure him. Why he thinks someone he has never met, who has shown absolutely no fantastic medical skills publicly, can cure him of his super special poisoning, the reader has no idea (we are not even sure why/how he has heard of her, let alone her healing skills) because she has only existed for around a week). Then when she tells him she can cure him, he is disbelieving that she can cure him!!! WTF, why are you there in the first place you idiot? Sigh.

She then stays in her room for a few days until suddenly the Author needs her to meet Prince #9. So she suddenly for the first & only time, decides to go out and explore the estate grounds, but gets tired and falls asleep and when she wakes Prince #9 is there.

Now with Prince #2, she is bold, confident, demanding & brazen (signalling in huge red lights to the readers that Prince #2 is indeed "THE MALE LEAD), but then when she meets the much younger Prince #9, suddenly she is polite, submissive, flattering towards him. WTF, suddenly she has a personality change.

Then when Prince #9 tells her the Empress Dowager is going to have a banquet and that one of her enemies is going to be there, so off course she decides to sneak into the palace to attend a ROYAL BANQUET. Yep, she is totally keeping a low profile. Her reason for attending does not even make sense. She is attending to find out more "info" about her enemy. And her plan is just to walk up to the palace and pretend to be a noble. What a s*upid plan?? Is the enemy going to tell her (a total stranger) his dastardly plan; or is she going to conveniently overhear him discussing his dastardly plan in a public space or is she simply going to hear information that she could easily get just by asking anyone who attended the banquet? Is she going to be saved from discovery by Prince #2? Is she going to attract the irrational & delusional jealousy of women at the banquet? Is Prince #1, the guy who bloody bought her and housed her in his estate going to recognise her? You too can find out and not care. (Seriously her entire plan is so moronic it is pointless) Meh.

Then she poisons someone no-one actually likes including Prince #1. And offers to cure that poison in an effort to blackmail Prince #1 into;

a) Presenting her as a Divine Doctor. Hello! isn't she trying to keep a low profile so she can recover her powers and face her enemies? Or is it someone she keeps saying whilst doing the opposite?

b) Giving her sufficient resources and money so she can cultivate. Hello x2! He was already doing that. In fact, she had just been given a chest full of gold & money. So what the heck is this request.

... and all this is presented as some brilliant master plan lol