I can't find servers...I'm not even sure it's trying as refresh is done in a fraction of a second and then nothing happens on the coop page.

Can you not play GOG games online?

I don't know if you can. One of the DRMfree "perks" is removed multiplayer, because game connecting to internet for mp is bad and drm. You could try playing with galaxy. Some games have mp that requires galaxy.

Even leaving aside unnecessary requirements like "be logged into our proprietary client," when a game lacks offline multiplayer options it in effect has similar results as DRM. A DRM-free store should not be selling games that include content locked behind DRM or DRM-like schemes. In terms of a game being fully DRM-free, these "stripped" versions are indeed the superior ones because at least it shines a light on the issue that these online requirements are not built to last. You could even put it as, one of the DRMed "perks" is removed multiplayer simply on a longer timescale.