Same problem here when using EA Desktop App, my display name is displayed all lowercase and the underscore between first and last name is removed. When using Origin, the name displays properly fine in the game, so it's a bug related to the EA Desktop App. It's very annoying, as Origin doesn't recognize EA Play via GamePass so we're forced to use the inferior EA Desktop app.
On a side note, it would be nice if EA allowed us to use whitespaces in our EA names, Steam, Epic Games Store, Xbox and Playstation players can always have nice looking names with spaces while we're limited to underscores and such. Or at least let us use the Xbox Account name with EA Desktop when using EA Play via Xbox GamePass for PC/Ultimate.
