I believe servers don't work anymore for bound in blood only Lan works.... gunsliger doesn't have multiplayer..And the first game only has multiplayer through Lan.Only way to play multiplayer games is through Lan if you can find people to play with you

Thank you so much for the knowledge. I bought these games hoping to play multiplayer online. I guess that will not work with these games. Maybe you can recommend something for multiplayer online games with GOG?

I really don't play multiplayer games I like play more single player games but I know that grim dawn has players and also has cross play with steam if you like arpg games.Also paradox games such as stellaris seem to have multiplayer .
You can check which games support multiplayer on gog here.Although be sure to ask if the games have active multiplayer before you purchase.

https://www.gog.com/games?sort=popularity&page=1&feature=multi&hide=dlc