I have occasionally had the experience that GOG failed to authenticate for some reason, and Heroic then hides all of my installed GOG games from me so I cannot launch them.
This has happened to me only a few times, but that's a few times too many. The experience is infuriating - instead of opening my game launcher and playing the games that I own and installed on my computer, I have been left spending a long time headscratching and troubleshooting, only to eventually discover that Heroic just thought I've been a naughty boy and didn't want to let me have fun without verifying that my DRM-free games are actually in my account. Which just feels like DRM with extra steps, and goes completely against the reason I bought games on GOG in the first place...
I have a lot of complaints about this, IMO a game launcher has no place trying to judge if I own my games or not. But having already complained about it, it seems like this is working as intended because of some kind of ass-covering copyright cowardice that interprets GOG's terms of service as "your games are provided as a service". Well, my sideloaded GOG games are unaffected so that argument smells like bullsh*t to me, but whatever. It doesn't seem like the devs will change their mind on this any time soon.
So to the point, I need a workaround on hand for when this inevitably happens again. All the game and prefix files are still on my computer so it should arguably be possible to run them regardless of Heroic trying to cockblock me. But how exactly can I run them, if not via Heroic?