Don't wanna be that typical hackernews guy but I couldnt resist... if your app is "quite complex" there is probably a way or ways you can break it down into much simpler parts. Easier for you AND the LLM. It always comes back to architecture and composition ;)
I have been bashing my head against the wall over the course of the past few days trying to create my (quite complex) dream app.
Most of LLM coding I've done involved in writing code to interface with already existing libs or services and the LLMs are great at that.
I'm hung up on architecture questions that are unique to my app and definitely not something you can google.