Did DOS2 really have much less content for non-origin characters? I've never played it as such, but I don't think there are any encounters or significant content locked away behind Origin characters. They add a lot of flavor, their background stories and some lore, but you still encounter all the same characters and big quests.
I'd expect same to be the case with BG3. It's impossible for Larian to read your free form text description of your past adventures, so you get a blank slate. The game will react to your class, race and actions within the game. Those shape your unique story.
