flatpak run org.kde.kdenlive/x86_64/stable Gtk-Message: Failed to load module "canberra-gtk-module" Gtk-Message: Failed to load module "canberra-gtk-module" libGL error: No matching fbConfigs or visuals found libGL error: failed to load driver: swrast Could not initialize GLX
Got some updates to flatpaks today and the issue seems to be fixed. Kdenlive launch normal again.