Oh yea if you are using distrobox on your system, and your xdg-open, distrobox-host-exec, or even host-spawn did not do anything, and you check you already installed flatpak, try to upgrade host-spawn on the container to it's latest version.

Do be noted that you need to download the binary manually from the github releases and replaced the one from distrobox built in host-spawn.

Also you need these variables on your host system or else distrobox might freak out when you try to kickstart the container after a host restart: DBX_SKIP_WORKDIR=1