Yet the standalone offline installed games won't run without libgalaxy.dylib (Mac) or Galaxy64.dll (Windows) which is responsible for outbound connections to https://galaxy-log.gog.com and https://insights-collector.gog.com?

To be clear: if you buy Disco Elysium on GOG, download the "offline game installer" without using Galaxy, install it, and run the game on a desert island, it will work (the network requests fail open). But if you try to run the game after removing the bundled dylib/DLL, it will not.

Why do Galaxy-free games ship with a mandatory dependency on Galaxy?