Something wrong with the way Dostoyevsky wrote them, according to someone who died in 1977.

I had to look up what "soulful" even means because I see it used so infrequently: "expressing or appearing to express deep and often sorrowful feeling" — while I cannot guess what would appeal to someone who would hire a sex worker as that isn't my thing in the first place, nor can I guess to the lived lives of those who so work, what I can say is that "observing someone being openly sad" doesn't pattern match my ideal for a fun time either when reading or when getting off, even though that is an entirely sympathetic and believable personality trait for a character who is a sex worker.

Especially believable in the case of characters that Dostoyevsky, who died in 1881, would have written about — not only because of the stereotype that Russia is even more grim than Country/Blues paints the USA, but also because while things like chloroform for childbirth pain relief had been used by Queen Victoria this was only in 1853 for the first use on the 8th child, but still advised against it for the 9th child in 1857*; or that likewise "it's a good idea to wash your hands between autopsies and assisting midwifes in childbirth" was only even noticed (and not immediately well received) in 1847.

* including by religious figures even though she was the head of the church