Ok, Larian takes a lot of liberties with the forgotten realms world/lore, but sometimes this makes the story really becoming disjointed and breaking immersion. Just a few observations, which are by no means complete:
(1) There are apparently Drow mingling with simple human scavenger groups instead of killing them
(2) Tieflings are not depicted as special or enigmatic, but as commonplace and simply 'humans with horns'
(3) An especially weird/funny moment was as two Tieflings were discussing how 'alien' Lae'zel looks while they are obviously looking much more alien

(4) Another situation was when I met a devil making an evil offer to accept his help getting rid of the tadpole - looking exactly like the Tieflings, but now suddenly being enigmatic and evil

(5) In the next moment, I again spoke to Tieflings who told me how weak and afraid they were of Goblins, looking exactly the same as the devil
(6) Another situation was meeting a mind flayer in the underdark, who, in the course of a few sentences, was introduced as good and living in the middle of a myconid spore colony
-> Baldur's Gate is a fun game, but this is often immersion breaking. If your Tieflings are just commonplace and another form of humans, they are boring and nothing special. If your Drow are just humans with dark skin, they are boring and nothing special.
Fantasy stories become interesting because of differences in cultures, species, powers. If everyone is the same, then there is no discussion, no conflict and no reason to read a story, watch a movie or play a game.