Remove unnecessary parts of the library. It could be that you have Excel files or screenshots that are causing the project to be larger than necessary.
Analyze your project to see where most of the data is. It’s a good idea to remove any unused dependencies, or unexpected data in the folder. However, if the size is directly related to the number of activities, you may need to divide it into multiple activities. I only find it unlikely, since projects mostly consist of text/XAML files.