Iv'e been thinking about it for a while now, and from all the rpgs I played the only game that ever gave me a complete blunk slate as a main character was Vampire: Bloodlines. in every other game there was some background to my character (in bg you were a child of god, in Kotor you were a blank slate but spoilers, in new vegas you were a curier, in jade empire you were a promising student, etc...). It worked in Bloodlines because playing a new Vampire is like playing a fish out of water and the real world is your origin. But I'm not sure it will work in Baldur's Gate 3. I'm trying to remember what was the character's deal in NWN1 but I didn't play much in that game so I don't remember. I do know that in NWN2 you had a solid origin... anyway it seems to me they need to think hard about how to make it happen. If it were up to me, I would give up the option to play as a companion and dedicate more time to writing some origins for the main instead.

Larian's Biggest Oversight, what to do about it, and My personal review of BG3 EA
"74.85% of you stood with the Tieflings, and 25.15% of you sided with Minthara. Good outweighs evil, it seems."