@Blotto I totally agree with you that the points you mentioned play an integral role in everything. But adding onto what
@Cataloons posted, if we go for her having NPD (which tbh I didn't believe she had, but now am starting to change my mind); we need to keep two things in mind.
First, a diagnosis for NPD is more for the people in the affected person's personal life, so they have a way to rationalize and cope with that person's behavior. Powerlevel, but whatever it's relevant, I have a person close to me with recently diagnosed NPD. He's not a bad person, but he has his moments, and now we all understand why, and know how to process his behaviors even though the diagnosis didn't do much for him other than make him feel guilty since he didn't realize just how bad he was. Does that make sense? It's not really for them (the affected), it's for us.
Secondly, the only form of punishment that works for narcissists is impeding their finances because it directly impacts them and they can't brush off less money as someone else being unreasonable. Like, "You think I'm an asshole? Well no, you're judgemental for thinking that, so you're the real asshole here," doesn't hold the same weight as, "Oh damn, I'm not going to be able to buy the thing I want." This isn't speculation, it's fact.
Her GRWM video was the only video she's ever had taken down by YT. When she saw just how quickly and unpredictably her money could be taken away from her, she quickly went onto the defensive. It's the only threat that actually got to her, you see. Her body, social life, familial life, etc., falling apart didn't matter, but less money does.
She freaked out even more when she saw that her massive unpopularity and blackout on Instagram presented an even more realistic threat to her maintaining enough viewership and jeopardized her lifestyle as it is, like Blotto wrote--which is why she had to think very, very carefully about how she was expressing herself in her video. How can she victimize herself, but not make it obvious that she was mainly concerned with the video being taken down? In that moment, reality hit her because she was about to lose out on money. Anyway, all this just to say that that's probably the main motivation for her rehearsed chimpout video.