Here's a pro tip:
Don't use Galaxy and the offline installers for the base game/patches instead.
For me, the translation of this advice: go back to mostly Steam for purchases. I'm pretty happy with Steam, just thought maybe GOG would be good to support. Oh, also I saw some streamers I follow get something out of purchases on their GOG store which seemed cool.
But for me, personally, it's only viable if the Galaxy app spefically is properly functional...like my Steam app is properly functional. If it's not ready, or never will be, for prime time there is a viable alternative. No interest, personally, in offline installers or whatever; probably just me, that's ok.