If you’re interested in creating an archive of your Steam games, you should check out the “download-steam-games” tool on the author’s GitHub. Although it has minimal documentation, it should be fairly easy to get it up and running. The author decided to download beta versions of KSP2 to revisit them in the future and laugh at the bugs. Initially, the slow internet connection on the server made it difficult to log in to Steam, so the author explored SteamCMD as an alternative. They ended up scripting the process to make it more efficient. The purpose of archiving games is to prevent loss in case they are removed from Steam and to allow access to old versions of games. The author developed a bash script and later a more enhanced app named “download-steam-games” for this purpose. The app currently has some limitations but is considered robust enough for production use. The author plans to address the limitations and add more features in the future.
https://lorendb.dev/posts/archiving-steam-games-for-fun-and-profit/