I know "Close to the Sun" does not require the Epic client be running to play, as I've tested it myself. Going to the game folder and launching the .exe works fine, and the game is effectively DRM free. When using Galaxy 2.0 however it launches the Epic client anyway. I don't know if this is a required issue or not, but given the goal of Galaxy 2.0 it would make sense to not have this requirement. I know a lot of Steam games do not require Steam running to launch as well.

The main issue here is probably determining that a game is DRM free at all. Neither Steam nor Epic label DRM-free games in their clients; I doubt they're providing the information at a more technical level either. DRM doesn't look like any one thing; it'd likely be difficult to figure out without manually experimenting with each game.

Unfortunately this is something that would likely be handled by a third party plugin handled by a community member. I assume the client is just telling the game to run through the appid and anything beyond that would require manual intervention on a title by title basis. Especially since so many of the games have optional Steamworks support and sometimes require command lines, different exes, removing or adding binary files to run without the client.

https://pcgamingwiki/wiki/The_Big_List_of_DRM-Free_Games_on_Steam

How would you expect them to know whether it needs the client? You're talking an almost impossible manual change ot each title that may not require the client to run.

Yeah, it's an impossible feature I'd say.

Can't you add a shortcut to the executable instead?

Why not configure the client to launch the .exe instead of anything else? Then it would just launch the game if possible, or launch the client if needed, in my experience. You could also have a simple toggle for not launching the client by default, or some other techy thing. I'm not an expert but it seems imminently doable to me if the goal is to run as much through Galaxy as possible.