Hello, thank you for your feedback. I understand your points, but please keep in mind that we are working within RPG Maker MZ, which comes with many limitations and does not have the same capabilities as a fully optimized engine for 3D elements, as you mentioned. Additionally, it uses a rather outdated version of Node, which is the runtime environment that RPG Maker relies on.
I’ve done my best to optimize everything, and all data is integrated into a single JSON file that RPG Maker can read quite easily. Even the images are encoded this way. My recommendation is to use well-optimized JPG images to keep the file size as low as possible, since a larger size could make the book harder to load and potentially cause issues.
Also, yes, you would need to have one book version per language you want to support in your game. It is not compatible with a table-based translation system, as everything is generated as a single file. I'm sorry I can’t help you further in this regard, but sometimes we have to adapt to the tools we have and understand that while RPG Maker allows for a lot, it still has quite a few limitations compared to other engines.
Best regards.