This book will involve Side Story Mecha and Blueprint Mecha.
However, there is one principle for all Side Story Mecha: no matter how impressive the mecha design is, as long as it's piloted by a Side Story character, it will be weak.
To put it another way, even if a Side Story character pilots a main story mecha, their combat effectiveness in the main story would only be considered second-rate.
Here's a simple formula: Strike Freedom + Murakumo Gai < White Uniform Yzak + Custom Zaku Warrior
This is mainly to prevent overpowered Side Story Mecha from stealing the spotlight. A prime example is the Powered Red Astray and its 150-meter-long sword. In this book, that thing would end up swinging too slowly, getting rushed down, and shot to pieces.
Additionally, please don't use real-world technology as a reference for Gundam universe tech, nor complain about what's realistic or unrealistic. Because in Gundam, something as basic as thrust-to-weight ratio alone already shatters the foundations of modern physics.
So let's just assume the world operates on entirely different rules. In short, you don't need to overthink Gundam technology—just roll with it.