Is there any particular reason the Gtk2 package has not been built for the latest DC? It is still available upstream. I know that Gtk2 is long in the tooth, but the Lazarus/FPC folks have still not adapted to Gtk3/4. I have been using DoubleCmd for years and have found that the Gtk interface suits my needs better than the Qt5 package I have set to ignore.
Since the gtk2 interface has not appeared, I tested with qt6. Doublecmd comes up properly, but gives an undefined error when closing.
doublecmd-gtk2 does not exist upstream in Arch, or at least not as of today. I'm going to follow Arch and have the now obsolete package removed.