Going to leave this review unrated, although I would have probably given it 2 1/2 stars because the plot from the 10% sample (which seems reminiscent of the Da Vinci Code) seemed interesting. I personally cannot determine with certainity if it is AI written, but the way the prose feels overwritten with floweryness without really telling anything feels sus enough.
To me, the majority of the problem is that it seems to be a second draft that cleaned up typos without developing the story. It feels like cramming a 90,000 word book into only 35,000 words. Usually, I feel plenty of books would shine tenfold if they killed a good 20,000 word darlings loaded with repetitive reminders of info the reader already knows.
In this book's case, we skip at least 5 chapters that could have cemented the MC's (Uhh.. Is it Arya?) escape from death during WWII, adjustment to a new adoptive family in the US and how this shapes her worldview. In hindsight, the barely mentioned backstory was like Vito Corleone's escape from Italy in the Godfather II film.
Arya has no PTSD, no struggles learning English or alienation with her new parents. Sadly, she is a Mary Sue. SO perfect and apparently physically attractive. Devoid of personality and can solve impossible Da Vinci Code type medieval puzzles with the snap of a finger. Mary Sues are one of my least favorite types of MCs because they can't keep me interested. There are gifted authors capable of creating such characters whose perfection is in reality, their greatest defect. Such defects then trigger variable types of conflict in the story where unscrupulous antagonists take advantage of this defect to further their agenda, or hell breaks loose and everyone now wants MC dead because they can't stand them. The vast majority of cases where the Mary Sue trope occurs, the character's flatness neither supports nor detracts chapter conflict in any way. Which expectedly happened in this book.
Whether the book was truly AI assisted or not, one telltale sign is that this book has a conveyor belt of equally flat random characters appearing in 2 paragraphs. Most of them don't even get a physical description. One character does a little something to further the Mary Sue's perfection, then they vanish from the story forever. Learning their names seems futile because they serve more as videogame NPCs fulfilling a preprogrammed function for Miss Mary Sue's perfection to shine. Which expectedly, makes it difficult to avoid skimming the pages in the hopes of just discovering the grandiose 'save the day' plot.
I will try to use a small degree of imagination and assume this story happens in an alternate universe where WWII takes long enough for a child to grow up and become trained in solving puzzles for mysterious agents working alongside (I assume) the US army.
In a nutshell, the story had the backbone for something that albeit not groundbreaking for the thriller genre, would have been a fun romp in an alternate timeline where WWII lasts far longer than 6 years. I would personally unpublish this edition, read a bunch of other thriller books starring warzone refugees. When in doubt, fanfiction writing is a marvelous stepping stone for novice authors where they can get used to storytelling within the comfortable constraints of a known IP.