In addition to the APK, the repo provides the opportunity to build a version of the app to run natively in Windows, MacOS or Linux, or to run in an emulated Android environment. If you want to build your own APK, I'll try to help with all the magic incantations that are seemingly required for Google's ecosystem.

I don't have the means to provide anything for iPhones.

Things to note: The app is intended for use with https://preferred.social/. Other PieFed sites don't have the API enabled, so won't work. It can't be used for Lemmy sites, and - likewise - Lemmy apps won't work with the site.