Where is the Linux version of GOG?
On GOG https://www.gog.com you can find a lot of great games without any digital restriction management (DRM) that run natively on GNU/Linux. Very good examples are of view Witcher 2 and Factorio. But without a native Linux client there is no reason to buy games on GOG.
A lot of Linux users complaint already, as they feel treated as second class customers. GOG Galaxy is using Qt, so there is obviously no reason to not get started with Linux support. But they lost obviously interest, read this for more details https://www.gamingonlinux.com/articles/looks-like-gog-galaxy-wont-come-to-linux-any-time-soon-as-its-not-a-priority.10183.
And they GOG Galaxy is as well only a 32bit application (Bug).
GOG Galaxy in Wine
Installing GOG Galaxy was previously broken with Wine whenever tested, but the latest versions do run fine. You can download it from here https://www.gog.com/galaxy. The version 126.96.36.199, 188.8.131.52, 184.108.40.206, 220.127.116.11, 18.104.22.168.. 1.2.45 didn’t work anymore as of missing a libraries.