I own an Xbox One S and a Windows 10 PC, I've installed GOG Galaxy on my PC, and I've configured the Xbox integration. I see in GOG Galaxy the Xbox games that I've recently played on my console. However, my Xbox is broken and until I can fix or replace it, I'm stuck with gaming on my PC. My PC isn't powerful enough to run most games, so I use my Game Pass Ultimate subscription's cloud gaming feature, which runs Xbox console games on Microsoft's servers and streams their audio and video to my PC. While the Xbox console games that I played on my Xbox One S (before it broke) appear in GOG Galaxy, the Xbox Series X|S version of Battlefield 2042, which I've played via the cloud streaming feature, does not. I'll have to look into this further, but it appears that GOG Galaxy's Xbox integration doesn't support cloud gaming.
On that subject, it would be nice if GOG Galaxy could not only launch PC games that a user has downloaded using the Xbox app, but also launch an Xbox cloud gaming session from the title page of a game that a user has access to via Game Pass Ultimate, if that game support's the cloud gaming feature.