Hehe, I’m pretty much in the same boat as you tbh. I’m currently writing a zombie story too but it’s a horror and it’s my first time implementing various point systems with complex branching and mattering choices/subsequent consequences. I’m absolutely determined to have complex branching, so if you are sure you want to go down that road too, I suggest you plan out a table that lists all of your gains/points etc for each chapter so that you don’t get lost within your own branches.
P.S I’d be happy to help you with yours (in PM or DM) if you ever decide that you need that. I’m no expert with branching itself since I do not have as much as experience with it as others, but I’ve managed some complex branching and kept them in my notes (branching based on points and choices made and also using flags+if/elif/else to branch consequences based on choices).