Defiant is the final book 4 from the Skyward series. The series has other works, written in cooperation with Janci Patterson, that can continue indefinitely but Defiant ends the whole thing. It’s reasonably translated as “Towards The End” in Bulgarian.
Skyward is about Spensa Nightshade, a teenage girl who wants to become a fighter pilot on a world that suffers a constant attack by alien drones. She has some special skills that develop over time, and she becomes one of the best pilots humans have ever seen. Her growth makes the first 3 books very interesting, although she gets nerfed from time when she faces new and more skillful opponents. I rated the first 3 parts with clear 5/5s and they were very enjoyable.
Book 4 is an exception and doesn’t get the full score.
You get all the wonderful world building, which is signature by Brandon Sanderson, his great storytelling and then you glue it with super-heroism and random nerfs to get this beautiful hardwood hardcover book spoiled. Spensa, who started the series as an underdog with a dream, is now comparable to strength to the Infinity Gauntlet Thanos. She practices instant no-energy teleportation and instant telekinesis of objects with unrestricted mass, can read minds, project herself elsewhere, and is likely immortal through respawning like a demon from Julie Kagawa’s Shadow of the Fox series. There are objectively no reasons for the book to last longer than 5 pages – Spensa can teleport the heads of her enemies 50 centimeters to the right and it would just end without her leaving her room. As if that was not enough, she’s in constant contact with two immortal, omnipotent, omnipresent, and omniscient AIs.
What are all those overpowered characters fighting for in 460 pages? Their enemies deserve the highest honors for lasting that long by using trickery and deception. The TL;DR is that they fight with boxes.

I think the Skyward world is exhausted and do not expect a continuation but Brandon Sanderson is a genius and can come up with a problem difficult enough for his demigod characters to resolve.
I gave this book 5*/5 on Goodreads but it’s probably closer to 3.5*/5 due to the lack of balance in the force.