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…
Phone, messengers/SMS, settings, browsers, and photo/video tools, in that order. Probably mostly because that’s the default location and where I’m used to them being.