What I’m saying is that Steam has the same problem as GoG - no guarantee that other players are available or will want to play multiplayer. It’s just that Steam is bigger than GoG and has been around longer, so that’s not as likely; but not a guarantee.
My understanding is that there is a fair amount of multi-player GD going on in Steam. I don’t play multi-player.
Based on Zantai’s post it doesn’t look like there is anything for the GD devs to do, and that it is up to GoG to make Crossplay happen. I could have misunderstood his statement though.
It sounds like you should contact GoG’s customer support and request that Crossplay be enabled for Grim Dawn, or ask if they have plans to do so.
They could at least implement direct connect by IP allowing people to use something like Hamachi.
I don’t think the devs really care about multiplayer though, the new expansion just added even more issues since people with it cannot play multiplayer with people who do not have it.
GoG and Steam are already cross-play compatible. The devs have to implement it, and considering the money Crate’s made it shouldn’t be that much of a problem. You’ll probably have to get a little info from GoG, but the responsibility is on the developers, not GoG to code it in for them.