Eh, Lolth might have been hot doo-doo back in 2nd or 3rd but 5th edition has seen her shrink rather...aggressively in stature as a deity. The retcons where the Udadrow/Aevendrow/Lorendrow stuff was introduced basically retroactively erased most of their presence in the underdark of Toril as a whole. A cult that Lolth hoodwinked into isolating themselves in a singular city in the underdark while drow with better sense (which is and apparently always was a majority) avoided. Meanwhile Lolth's motivations-,multiversal conquest, revenge against the Seldarine, shaping the drow through the brutal crucible of drow religion and society to be a reflection of herself, ambitions of drowing surface elves and humans into worship of herself....has eroded via the books into from what I can gather could best be described as 'lol, chaos' and ennui.
Plus y'know. aforementioned singular city where her worship is centered is
in the middle of a revolution.
As happy as I am to see she has something of a role in BG III (at least when you play a 'Lolthsworn' drow/cleric of Lolth), I am doubtful of 5e's version of Lolth to hold down the position of overarching villainess of the setting in her current state unless things drastically change.
Menzoberranzan is not the only Drow city. Similarly, it also not the only Drow city that worships Lolth. Menzo is just the one most dealt with in the books before of RA Salvatore and Drizzt.
The actual largest Drow city that worships Lolth is located under Thay and is about 4 to 5 times larger than Menzo.
Oh I'm aware. At least in the past that was the case. Hell Menzo was a third-generation Drow city and not all that large by their standards IIRC my drow lore correctly (I thought the one underneath Calimshan was the biggest, but I wasn't keeping track), but all that got retconned. The new lore recontextualizes everything to the point that drow cities outside Menzoberranzan are of doubtful canonicity. Like the 'udadrow' (what they are calling lolth-following drow as we knew them previously) are defined as a cult that she hoodwinked into sequestering themselves in the underdark so she could control them. That is Menzoberranzan under the new lore. Just one city-state. Now maybe WoTC will re-canonize the other cities. But right now Udadrow(or Lolthsworn drow as they call them in BGIII) means from Menzoberranzan.
There's still quite a few that WotC is talking about. Guallidurth, the city under the Calim desert, isn't much bigger than Menzo in 5E time frame (only about 50% larger), but was much larger than Menzo in the past. But both still pale in comparison to the city that is under Thay (can't find the name of it) which at it's height was well over 100k Drow and about 500k slaves (Menzo at it's largest was around 20k Drow and 60k to 70k slaves and Guallidurth was around 80k, not sure if that's combined or just drow).
And the other two "Drow" groups I really wouldn't consider Drow as the one is the Starlight Elves (northern group) and I can't remember what the southern one is, but the southern one is closer to that of Green/Wild Elves (which the Drow were originally Green Elves) and are more like Wood Elves in mentality. The Lolthsword Drow are by far the largest group that remains of the "Green" Elves.