I only got into Touhou in 2019 but I always get an odd sense of faux nostalgia booting up EoSD or IN, not because those are the ones I started with (they are), but something about the visuals and menus evokes memories of playing old PopCap games in the 2000's, though I guess their release dates don't stray too far from each other.
As for music, I'm pretty sure I stumbled upon U.N. Owen before either of those, kind of a given.