I know how to change it for other versions, but that method doesnt work for the GOG version.

Im talking about the PLAYER name, not your ruler name. Its visible in the galactic community if you select your proposed resolution, it will show your country and it will say "played by [PLAYER NAME]". I want to change that name. Any ideas on how to do it?

Im talking about single player by the way. The multiplayer name has no effect on the name used in single player.

Edit : Did more testing and it seems you must go to the MP screen to select a name first BEFORE it will take effect in single player, and it only takes effect on new single player games.