Few things which makes achieving reproducible/deterministic builds hard are - timestamps of generated/compiled files, continuously updating versions of build tools(+support libraries), output binary difference compiled across different OS.
We can use docker based build system for this, but it would require very carefully configured Dockerfile to keep the build tools+libraries on specific version. And if we do a pre-built Docker Image, then the Reproducibility of that Docker Image has to be proven first. It is indeed a difficult task, but not an impossible one. With F-Droid providing a sound framework for reproducible build generation, I believe we would have majority of large Android Apps reproducible in next few years.
+1 for recommending Fossify over 'SimpleApps'
Extending the reply for 'Sandboxed Play Store .. F-Droid .. Aurora Store' -
I'd recommend you have both - F-Droid and Aurora Store. If you need to access the Play Store subscriptions, then you'd need to install Play Store as well.
I usually open the Google Maps Web in an incognito window. But I'd definitely try the App you recommended.
Just a quick question, if you happen to know the App workings - Does this App clears the data of web-view on close? Or the Search history persists over the usage? Apart from the android app data clear option, is there any internal auto-clear option?