I also have a (sort of) DnD lore question. If Lolth is my warlock patron, what subclass of warlock would that most likely be?
So the easiest answer would be to say Cleric/Paladin as those who make pacts with Lolth end up more as Clerics and Paladins than Warlocks, but assuming your character does not become a Cleric or Paladin, there are a few that I could see working. The first one that makes sense to me lorewise is Celestial as Lolth is in fact a goddess and has divine power, this would make one's character closer to a Priest of Lolth (and for lore friendliness likely should be Female). Alternatively, the Arch Fey possibly could work because she is an Elven God, and that would be playing up drawing on her Elven Aspects, perhaps focusing on the Drow parts. The last 5e subclass that I could see working for Lolth as a warlock patron is actually Hexblade, slightly flavoring it to weapon and powers granted by her, and this would go pact of the blade.
However, none of these options are in BG3 currently, so if you wanted to RP as one right now, the closest is likely GOO for the manipulation aspects but even then that is a very large stretch.