Currently it is a “viewer” (renderer with usable UI) and editing features are experimental.
They only release their APK to Google Play for whatever reason, but you can use F-Droid to get it
Bugs can normally be reported to their bugtracker and you can join their forum for more community support!
Downside: the editing features are VERY rudimentary, while the app is only about 50MB (⅕) smaller than Collabora-Office, which has better features overall.
The entire point of F droid is that they reliably, openly and securely build APKs which are reproducible and guaranteed to correspond to an upstream source tarball. Then they sign with their own keys since they are the ones who do the actual building