It's literally Malady from DoS 2, like it's the same voice actor.

She's got a great voice, wonderful tones....but it presents two problems for me:

1. It reallllllly makes it hard to argue against people saying this is DoS 3, rather than BG 3, since the primary voice you'll be hearing is an actual character from DoS 2. John Mayer, the original narrator from BG 2, is still alive and still working. It would have been a nice call back at least. It does lead a bit into my second problem with it....

2. Literally everyone has British accent in the game. Narrator, random goblin #46, Drow who've never seen the surface world before....and literally travelers from another plane of existence (Githyanki). Everywhere you look, everyone has a British accent. It makes the world feel smaller than it should.