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…
here are my 4 non-Foss apps, out of 27 total on dock (yes on the dock, using folders)
🚫nordvpn
🚫obsidian (sync disabled)
🚫@voice aloud tts
🚫MS Swiftkey settings (true privacy threat i know, but Asian lang. support is essential & it runs w/o internet perm., w/o play services, and kept in incognito.)