Try highlight on one of the icons. I am guessing whatever color
scheme you are using has the font color defined as white.
I assume that by "highlighting", you mean "selecting". That does make
the selected item's name visible. But when a directory has many items, that still
makes finding the desired item(s) tedious.
I am not sure where that is really set. I can see at least a theme
setup in gnome-tweaks -> appearance, I don't see were you can define
specific colors mappings.
The "Tweaks" tool shows the theme for "Applications" set to
"Adwaita-dark", same as before upgrading to f31. "Files" was fine
before the upgrade. I deliberately chose a theme with a dark background and light text;
it's easier on my eyes. I can try other themes, but that doesn't change that
something seems to be broken in f31. It seems to me that something in f31 is not handling
backgrounds properly. The xeyes problem that I noted in another thread earlier this month
also seems to be a background issue. Has anyone else seen these or similar problems? Is
this a legitimate bug? Should I submit a bug in the Redhat Fedora Bugzilla?