Necropolis will always be the most recognizable to me, mostly because City of the Dead is reused in Fo2 and FoNV. Speaking of horror music there was one that was cut out in Fo2 that would kind of fit the bill.
https://youtube.com/watch?v=s3rRi0LgVRo
I have never seen this track mentioned, nor is it listed anywhere on sites like TCRF or the Fallout wiki. This means this is either fake or a newly "released" unreleased track. Would sound lovely in a mod or a new location, maybe the new version of Restoration Project can insert it somewhere.
Because the goals don't align. While all these games are RPGs. FNV tries to make it so you make your own story. There are enough elements in the game that you as a player through playing can build a coherent and continuous narrative for yourself and those elements for the most part work for a varying type of story. Caesar can be a villain, a friend or irrelevant.
While Starfield and friends are quite literally about playing a Role. You don't make a story, you don't even change a story your PC and your interactions are as in depth as a poster. The focus is about you looking the part. You play a role the same way someone on a billboard plays a role.
The actual RPG part of their games has gotten so twisted over time that all the other aspects like the core gameplay, radiant system and map design are disconnected from the story and the RPG aspects of it(to be fair in FNV they aren't even that well connected) where nothing you do in the story affects your gameplay or vice versa.
Thing is that in the earlier Bethesda titles, you could definitely roleplay as a character of your choosing, just like in Fallout games. The last games that actively let you do that to some degree were Fallout 3 and Oblivion, Skyrim onwards you were just a generic pre-made character that Emil chose for you. Hell, Skyrim wasn't even a roleplaying game, it was an action adventure with a shitty skill tree.
Thing with Starfield is that you could tell they REALLY wanted to put some stock into your character's background, which would make roleplaying viable in their games again...except none of these backgrounds actually do anything substantial, aside from the one that adds your parents. Some are so meaningless they might as well not exist, for example the Snake Worshipper one. Aside from the fact that Va'runn as a faction was cut almost entirely, the few interactions you do get with this background don't even paint you as a member of their religion. The zealots still attack you, and at one point when their ethos are explained, you apparently don't have any clue what your own religion is all about and need to ask for more details. Not like backgrounds would matter anyways, with how the story forces you to make friends with Emil's treehouse of friendship, to the point where some of these characters will literally tag along with you until you complete their main quests, against your will.
It's crazy how Todd could have just copied Obsidian's homework and started incorporating features of New Vegas as standard for their games, I bet they could even re-write history and claim these additions as their own, since it is still "technically" a Bethesda title. Instead, their egos demand that game be buried as much as possible and force their own brand of non-RPG slop onto the masses, even when it starts ruining their products. Even something like the recently released Fallout London fanmod blows absolutely everything they're done in the last decade out of the water.