I'm a nerd, if I wasn't I wouldn't have named my account after a favored D&D character of mine, but I would really like a way to actually change the display name for the GoG version. I assume that the steam version would adopt my Steam display name, so the GoG version having no way to change my display name is a big negative for me.

Open a new GOG account under your prefer name and use it to login into the game.

I won't get in trouble for playing a game that said account doesn't own?

I don't know, try contacting support (come to think on this you could ask them to change your user name).

I tried making a new account but the GoG launcher won't let me change the account that is active in the game anyway...

Fuckin hell this is needlessly locked down.