That isn't the experience with flatpak though, flatpak is the same as using apt-get or any other package manager except instead of getting stuff from your distr

That isn't the experience with flatpak though, flatpak is the same as using apt-get or any other package manager except instead of getting stuff from your distro's repositories you get them from some flatpak repository you have to configure (some distros that provide flatpak might have flathub preconfigured, though not all of them do that). AppImage does provide that "download an exe and double click" experience but it assumes you have made said portable Linux binaries (and they still have the drawback of dragging in a bunch of libraries you most likely already have in your distro).