Kamonichan: My friend found out about GOG and said it would allow us to crossplay games. I have Remnant: From the Ashes on Steam, and he has it on Xbox PC. But after every account we have (Steam, Xbox, Epic Games), we aren't able to invite each other to join the same game. We were told that using Discord's game overlay would allow us to do that, but the option to invite each other didn't appear.

So I guess I have the following questions:
1.) Is it possible to crossplay a Steam game and an Xbox PC game by using GOG?
2.) If it is possible, how do you do that?

All attempts to find an answer on the web lead us to instructions meant for developers, not users. If the program doesn't work as advertised, then it'd be helpful to know that so that we can stop wasting our time.