Great points. Thankfully the companions do not always suffer from the main character syndrome of DOS2.

While DA:O is probably the best example of a great origin system it does not fit with the final version of Durge. Both BG1/2 and DA:O tell a zero to hero type of story while BG3 is more of an amnesiac hero like one like Planescape Torment. The best origin system for this type of story is that of the most underrated CRPG, Pillars of Eternity. In this case the background of your Durge changes based on your choices in visions or dreams similar to the noblestalk sequence.

Here's how it would be implemented
Example 1:
Background: Noble

First dream is of your adoptive parents who depending on your choices were honorable, abusive or indifferent. In this case the parents were honorable who taught the young Durge to be noble and stuff until one day the Urge awakened and they ended up dead. Now this good Durge tried to resist but without the tadpole just couldn't and ended up in the Temple anyways.

Example 2:
Background: Acolyte

Dream of the temple with the same idea. Let's say you hated the temple and the false gods and couldn't wait to punish everyone and get out of there. Urge kicks in and you're pretty happy about the murder fest that follows and willingly go to the Temple.

Now mix and match different backgrounds and current motivations and you get a different RP experience every single run. You could play the noble Durge who tried to resist in the past differently in the present and of course it will change the motivations of a certain woman who betrayed you. Unfortunately, everyone's Durge is exactly the same.