I believe Flatpak is linux-only. There's a UI to edit Flatpak settings from KDE settings or you can use flatseal. You can do tons of neat things with it. You c

I believe Flatpak is linux-only. There's a UI to edit Flatpak settings from KDE settings or you can use flatseal. You can do tons of neat things with it. You can also cut off environment variables, cut off the x11 socket, only allow certain dbus channels, etc. You don't need a docker container or anything, Flatpak is a container technology.