Currently, the minimum size you can get for Android is about 15mb (for standard, Managed workflow). Assets like images, fonts or icons, have the biggest impact on the size of your application. What can you do?
Use expo optimize command (check --quality option)
Load the largest assets from an external URL, asynchronously, in expo/AppLoading or directly in the component
Use only the necessary icons and fonts weights (not whole sets)
Do not import entire libraries, but only the most important functions (something like import get from lodash/get)
Compress all static video and audio files as much as possible
Use “native” components as often as possible, sometimes it’s not worth importing the entire UI library for 1 or 2 elements…