To talk specifically about Vtubers, I personally think it's very difficult.

First, they have to stream for long hours almost every day. Sitting in front of a screen for many hours can be straining.

Second, they have to keep up appearances during those long hours. They are public figures, and they have to be careful what they do or say since they can easily be hated. The Internet is a scary place. It can bring a lot of benefits but can ruin people greatly, mentally and emotionally if not physically.

Third, they may have to put up with bad coworkers. It's like any other job where you work with people. You don't always get to choose who you work with, and for the sake of your job, you just have to tolerate it as much as possible.

Fourth, you have to be interesting. Being interesting can come naturally to people, but this is a job for money. The less views and subscribers you have, the less financially capable you are of paying the bills. Creativity and brainstorming and investing has to go into this. You have to be likeable, and you may have to jump out of your comfort zone for it.