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…
Vivaldi - FOSS Weather - FOSS FB Reader - not FOSS but soon to be replaced with Librera FD when I finish what I’m currently reading Clock - FOSS Camera - not FOSS