https://github.com/Heroic-Games-Launcher/HeroicGamesLauncher
It combines Epic Games Launcher, Amazon, and GOG game libraries, all into one free and open-source client that also works great on Linux! I don’t like Epic Game Launcher’s footprint, but like that they gave me GTA V for free. Heroic Games Launcher lets me download GTA V no problem on Windows, and it even hooks up to system wine on Fedora Linux!