When I attempt to install a game via GOG Galaxy 2.0, a dark pop up dialogue comes up, has two buttons: "Cancel" and grey-out "Continue" and where what I assume would be text is just an animated twirly arc going around in circles forever.

Is there something I can do to rely on GOG Galaxy 2.0 to install stuff, or should I just skip it and download and install directly?

I've had this happen almost every time I try to install with Galaxy 2.0. Exiting the program and restarting it usually causes it work if you install the game immediately. But even when it does work the download rate is far slower than directly getting the offline installer from the website.

Galaxy 2.0 does recognize when you've installed a game with an offline installer. So it's best to just use those.

Yes that does remove a good deal of the point of using Galaxy 2.0, but that's the current situation.

That is... crazy. I know it does not always detect from the install process. As an example I installed "Shadow Warrior Classic Complete" and GOG Galaxy regards it as not installed and using the "Scan folders for GOG games" is not good as the scan takes for ever even when I direct it to scan the directory of a specific game