Regarding human technology and Alfar magic:
There is significant 'lore' or background information that we don't have regarding how technology and magic work across all the worlds linked by Neverwhere.
The Alfar include powerful magic users but does their 'center' of magic - Alfheimr - limit the use of technology and other non-elemental forms of magic in that world?
I say non-elemental since the two queens are masters of fire, earth, air and water.
We saw a damas obscured by a powerful illusion spell during the Neverwhere attack on Medb. Is this form of magic someone else's specialty, where there are humans and Alfar who can use those spells but the true masters are the dark elves or some other species?
Are all forms of magic and technology tempered/buffered to some degree by some world effect of Neverwhere?
Does each world act as a center for their form of technology/magic, which works at 100% while other forms of tech/magic are diluted, with some kind of world dampening effect - the more powerful the non-native effect, the more diluted the power of that effect?
I can't see a human nuclear weapon working at all in Alfheimr and this type of effect would explain why a human faction has not just rolled into Neverwhere and Alfheimr taking them over and launching invasions of other worlds for resources/treasure.
I think a lot of this will be cleared up in season 2 as this knowledge becomes more relevant for the MC to ask about and for that lore/background information to be revealed.
Cheers!!