basically RetroDeck is a one and done type of deal. one package (flatpak) that has everything pre-configured and good to go as opposed to say RetroArch where you have to pick your cores (emulators) and what have you. on say a SteamDeck something like RetroDeck is naturally going to be easier to use and set up but when it comes to a Linux desktop it’s all really a non-factor. Like for example most distro repos have either a complete library of the cores for Retroarch or you can pick and choose which ones you want. like on Arch for example the package “libretro” will give you everything or on Nix/NixOS you can pick and choose which ones to install with Retroarch.