GOG's games have long felt castrated. It used to be that current games weren't getting the full treatment, with delayed patches and all (if the game ever got patched actually) but now even older games are getting less love. Sadly it's not just GOG's responsability. Night Dive et al started to "align" GOG and Steam's versions of games and there's little reason to stay at GOG considering most Steam games are DRM free already, you can use offline mode and you'll get patches in time and etc.
Haven't personally noticed GOG get worse in this regard but Steam has certainly gotten better. Used to be nothing old ever worked out of the box. Ever since they started to work with Codeweavers on Proton they've easy been the compatibility leaders in at least the Linux space.
Well if you use Linux Steam is definitely kinder to you than GOG. A huge chunk of their overlapping games are fully functional on Linux while that's not the case with GOG. GOGs' problems are more subtle and have been increasing with time but off the top of my head I can mention the following:
-As I said, outdated patches. Some critical cases were the games weren't even patched at all.
-Missing DLCs for games that are available on Steam too.
-Multiplayer and online functionalities are often not included or reserved to Galaxy users only.
-Games with nudity have to be patched manually, while Steam offers it right from the start.
-GOG themselves are starting to offer little bits of content for CDPR games that are only available if you play the game through Galaxy.
