As far as I'm aware all modern Desktop Environments and distributions support portals and have them preinstalled
This allows to use native file picker for system specific environment (Kde, Gnome or any other implementation that's installed on the system)
Currently AWT file chooser causes crashes on Kde systems (including my own) https://github.com/JetBrains/compose-multiplatform/issues/1279
As an alternative Xdg Desktop Portals can be used https://flatpak.github.io/xdg-desktop-portal/docs/reasons-to-use-portals.html https://flatpak.github.io/xdg-desktop-portal/docs/doc-org.freedesktop.portal.FileChooser.html
As far as I'm aware all modern Desktop Environments and distributions support portals and have them preinstalled This allows to use native file picker for system specific environment (Kde, Gnome or any other implementation that's installed on the system)