I decided to implement the change where the model outputs a number between 0 and 1 to represent somewhere within the high/low range of numbers it can currently guess between, and also added a new input to the neural network telling it the number of guesses so far. Both of these changes drastically improved the model and now it averages around 9 guesses to find the number, which is an amazing result. I only got to this after playing around with trying to change the fitness function again to not much success, but I am glad this idea worked. Next time I work on it I will add a user interface on an online website with the final trained model so people can try it out.