Svatalves probably have defenses in place for that. Though Eb just walking up to Harry's apartment makes me think that maybe they aren't as impressive as we've been led to believe.
I think it's some of both. From everything we've seen and heard, the Svartalves are not to be messed with lightly.
But Eb is
good.
I don't think the Svartalves are really major powers; Etri seems pretty high up among them, and yet everybody considers the assassination attempt in PT a plausible threat. I don't think that would be true for any of the
really powerful Fae.
Sure, Etri chops up a decently powerful (non-minion) Fomor in "Bombshells". But that's a long way from blasting apart two Lords of Outer Night with one spell like Lea does. I doubt he's even comparable to Molly or the Eldest Gruff.
I think the Svartalves are mostly dangerous because of their magic-technology and preparations. So nobody really wants to attack them, even the major powers, but they're not a major power themselves.