Reinstall gnome by sudo apt reinstall gnome then reinstall the portal services by sudo apt install --reinstall xdg-desktop-portal xdg-desktop-portal-gtk xdg-desktop-portal-gnome and then after that restart these services bysystemctl --user restart xdg-desktop-portal systemctl --user restart xdg-desktop-portal-gtk systemctl --user restart xdg-desktop-portal-gnome and also reload the user manager daemons by systemctl --user-daemon-reload and your system will now run perfectly. No more terminal, file-manager or settings lagging.