I made a proof of concept for running Epic Store Games from Steam Deck UI

• legendary

  268 4,430 7.1 Python

  Legendary - A free and open-source replacement for the Epic Games Launcher

• HeroicGamesLauncher

  755 7,226 9.6 TypeScript

  A games launcher for GOG, Amazon and Epic Games for Linux, Windows and macOS.

  

Currently you would still have to drop into a terminal to install the games, but I know that there are other tools that might be able to help with that in a UI/Deck friendly way. https://github.com/Heroic-Games-Launcher/HeroicGamesLauncher

• WorkOS

  workos.com sponsored

  The modern identity platform for B2B SaaS. The APIs are flexible and easy-to-use, supporting authentication, user identity, and complex enterprise features like SSO and SCIM provisioning.

  

• steam-buddy

  11 221 8.0 Python

  A web interface for managing Steam remotely

  

You can also use https://github.com/ChimeraOS/chimera

• GameHub

  3 5 0.0

  All your games in one place (by dotevo)

There's GameHub fork, sporting GOG, Epic Games Store, Steam, Humble Bundle and Itch.io: https://github.com/dotevo/GameHub

• Ice

  4 833 0.0 Python

  Application to automatically add ROMs to Steam (by scottrice)

https://github.com/scottrice/Ice Interesting project adds roms into Steam and downloads metadata. I believe it's able to parse and edit the shortcuts.vdf file to add the games into steam itself.

• SteamLauncher

  4 28 3.3 C#

  A LaunchBox/BigBox plugin designed to allow games and/or roms to be easily launched through Steam.

You could look at using steam api interface IClientShortcuts instead of editing the shortcut file so steam doesnt need to be restarted. You can add/remove nonsteam games instantly etc. For example SteamLauncher plugin (c#) (https://github.com/lahma0/SteamLauncher) for LaunchBox does this. (Do note it does things a bit differently and uses one hidden shortcut for all games but you could create one for each game of course)

Suggest a related project