Anyway, I'm thinking more about city dwellers who generally live in apartments.
That’s a lifestyle that makes significantly less sense for remote workers in the long run though.
This is the original one I saw when I considering doing it: https://www.youtube.com/watch?v=pABvTWSxOes
One more DIY with fabric and rock wool: https://www.youtube.com/watch?v=tPEouyiEt3Q
I had to wade through a lot of conflicting advice when I did it.
I suspect a big factor is that most people do only a handful of implementations, and might overgeneralize the lessons they draw.
Also, for a given structure and environment, most people can only afford to try 1-2 soundproofing approaches (wall structure, ventilation, etc.) So it's hard to know if they picked a good point in the tradeoffs space.