Funny you should ask. I just listened to a podcast with an interview with Swen, and that came up.

https://www.usgamer.net/articles/ax...-on-baldurs-gate-3s-early-access-release

Skip to 26:15 for the start of Swen's interview, but the pertinent question is at 33:30. Swen claims that the backstory for the custom character has as much depth as that of any Origin character. At 36:00 he says that the "Who do you dream of" character is a pretty important character, key to the custom character.