In the words of Jack Sparrow "sea turtles mate". Just take what information you think you know and forget about it. Larian hates memberberries, lore, immersion, cogent stories or any references to the previous BG games. Don't mention D&D either shhhh "they are listening" the strawmen will get you.
But seriously Menzoberranzan is about a third of faerun northeast of Baldur's gate. According to the map about 2500-3000 miles. Definitely netherese magic teleportal distance and I hear the Menzoberranzan's just signed a contract with huawei to get 5G installed. You can walk there in a day considering the sun doesn't move.
