What do you mean, "a little lacking"? What do they lack, that you need?
It's unlikely that anyone that reads this will have specific RA8875 experience, as there are so many displays. Even if so, how many of those people would be willing to wade deeply into your code without any help from your side? So it's unlikely to happen that way.
What specific things don't you understand about the .h file? If you have specific questions, you could post the lines in question and state what misunderstanding you have.
Lastly, have you undertaken any general research on the IC? For example, looked for data sheets and other documentation?