I have tried to be aggressive about keeping the size of the app down as it has grown. I made a specific decision early on to avoid image assets and I went through quite some hassle to enable build features to keep the code small.
A while ago Google introduced a new way to package and distribute Android apps called Android App Bundle.
Previously when distributing an Android app, the developer would produce an Android Application Package (often called an APK, based on its standard file extension) that included everything needed to run on a variety of Android devices. This could include things like assets at different resolutions and code for different device architectures that were not all needed on any single device.
It was possible to produce different APKs that were more specialized but it was quite a bit more effort to setup a build pipeline to produce them and distribute them. With App Bundles, Google Play does this for you. An App Bundle contains the same wide array of content for different devices, but Google Play generates a device specific APK for each device that downloads it.
The result is quite staggering - much more than I expected. The graph here shows the size of the app in MB over time, with the conspicuous drop at the end when I switched to using App Bundles. (One interesting thing to note is that the line splits into two at the end. The size is now slightly variable based on device and the split represents the smallest and largest APKs possible).