GOG Version 2.0 coming soon and will be in Beta soon.
Sign up here to try to get into GOG Version 2.0 Beta -
https://www.gogalaxy.com/en/So, besides GOG games that have this stuff built-in, it's built for cross-platform stuff across other platforms.
So it'll also let you manually add Non-GOG Games (or games w/ no client support to any client) and Customize your Library; do stat tracking and Time-tracking; Cloud Save Support; try to unify your Friends list and chat lists across platforms; and other stuff.
Basically, besides being GOG Galaxy - it's also trying to be
PlayNite and
GamePlay Time-Tracker built into one app.