Go to your phone homescreen and look at the app dock (the bottom row that contains some apps and stays the same when you switch pages).
Which are yours? Any FOSS apps?
In my case, they are FDroid, Signal, Threema, Firefox and the defaul Samsung camera app. So, 80% FOSS…
@lemmydividebyzero
They are Fossify Phone, Fossify Voice Recorder, Fossify Camera, Fossify File Manager and Settings. So, 80% FOSS!