In a cryptic world, the biggest stranger Estelle meets is herself. Decent hook! I don't know what a cryptic world looks like, though. Hopefully clarified below.

Living with her guarded foster mother in Montreal, she flounders in a tangled web of unraveled mysteries, disconnected from the outer world she thinks she knows. This is pretty vague. What is the nature of these mysteries? Estelle pursues for need to strike "for" a life full of possibilities but unaware of the lurking threat of a sinister network of manipulation and villainy called Apex who’s in the hunt to exploit the innocent to destroy order. I don't know what this means, or why Estelle would be targeted. Your wording here is very vague so I feel like I don't have a good grasp on what the actual threat is. When she runs into her menace in the open far from safety, Estelle quickly realizes she is being hunted.

Fleeing for her life, Estelle escapes to her forgotten home of Auria, a fantastical world hidden in the shadows, where traces of her mysterious past linger. How aware was she of this mysterious past? Had she entirely forgotten this world? Or was just unable to access it? Realizing she is unknowingly gifted and powerful in her own ways, she is vulnerable to the various advances of Apex and the trials that await her, challenging her insecurity and her trust in others—including herself. What connection does Apex have to Auria?

When betrayal leads Estelle and her friends When did friends come into this? to a spiraling downhill of no return, it takes the power of self-sacrifice, confidence, and community to battle against Apex’s reign of evil and rescue all those who are captured. Even though Estelle saves Auria and finds salvation in herself with her new family, the mastermind behind Apex is still on the run and ready to retaliate with revenge.

THE CRYPTIC WORLD is a YA contemporary fantasy thriller of 87,000 words, the first in a planned series with the sequel currently in the works. I am a psychology student at Arizona State University with a creative passion of building enchanting worlds and challenging controversial ideas. I believe my book will appeal to young readers with its themes of confidence and innocence along with thought-provoking ideas embedded in the plot that will leave the reader questioning their reality and how they are represented and used in society.

This ending para is great, I really like it. However, you are too vague in your paragraphs above. All I know is that there's a girl with some abilities from a foreign world who never quite fit into reality, there's a bad force after her, and she isn't terribly confident in her new role. That plot that I just described could fit any hundreds of magical or fantastical novels. You need to get details into this to illustrate what makes your novel different from the hundreds of others that fit that mold. Also, you definitley need to find a way to make this a standalone with sequel possibility. Fantasy is a very tight market now in YA and pitching a debut fantasy series would be difficult.