How to make Flatpaked GNOME apps look okay on KDE ?
They all look bad for some reason, sometimes even completely unreadable because of the lack of padding between lines of text or dark-on-dark text color.
I made some notes while I had a problem with Zim flatpak not following Breeze GTK theme:
https://docs.flatpak.org/en/latest/desktop-integration.html#applying-themes
//The applications will try to match the system theme currently being used, if it corresponds to any of the Flatpak themes installed, and will fall back to Adwaita (if they use Gtk2 or Gtk3) or the default Qt theme (if they use Qt) if a corresponding theme isn’t detected.//
So I executed flatpak override --user --filesystem=xdg-config/gtk-3.0:ro and it didn't output any error, but it changed nothing regarding apps that look bad, unfortunately...