I found the following article quite thought-provoking. (It's long). It describes the genesis of the dark urge story-arc, and highlights Larian's style of story development. There were different beginnings of the DU story. The one that is in the game was only begun to be written after EA was released.
There are several other instances of existing storylines, (proven or not) that had impoortant changes after EA. It seems to be Larian's style.
Another policy from the studio is to fully work out choices that will maybe never be explored by players (or only by a a handful)

So what with the upcoming games ? Will they keep this way of working, or start with a solid storybook and not deviate (too far) from it to keep a healthy logical story from start to end. And also put less focus on exotic deviations to solidify the main line ?

Or will they continue the somewhat chaotic changes "on the way" -- which actually may be the reason why the product is loved so much by players -- but which leaves a somewhat bitter taste afterwards because so many things "don't add up".

I'm divided into deciding what would be best. I liked BG3 so much. 1500+ hrs now, but I'm also annoyed by the plotholes. Knowing that it is not even possible to reconstruct a complete and consistent storyline.

https://www.eurogamer.net/the-making-of-the-dark-urge-in-baldurs-gate-3