gOS latest build feb 2024 A14
Settings > apps > default apps

Why are there only 4 apps, and we can't choose default app for replacing the provided Files app and Gallery app and Camera app ? I believe we can in every other OSes

Because then, at each thumbdrive plug, the notification button "Explore" opens provided Files instead of my preferred filebrowser. (Files is dumb enough when ordering to move a file, say on a folder next to it within the current folder, to bring back the user all the way down to default "root"folder, and one has to dig in many folders to get back to where the file was)
And then the lockscreen bottom shortcut links to provided Camera app.
And then the provided Camera app, which remains convenient for

  • not prefixing the output files with PXL_
  • removing the metadatas by design
  • for a use on any profile willing to upload somewhere and not dedicated to pure photography

cannot links to my preferred gallerybrowser

  • [deleted]

I don't know what OSs you have used but 4 apps in the default app list has been a thing for many, many years.

Picking a default can be done when opening different file types.