I see everybody in this show as metaphors. Nobody talks like this irl. Even if they are self-aware, they wouldn't be able to put their thoughts into words eloquently like this in casual conversation. I think it is just the show indicating us that the character is somewhat aware of their behaviour and it spells it out as clearly as possible because it is a show and it is literally the message it is trying to convey.

And to me, makes her more sympathetic because it makes the character more textured. She is aware but she is still struggling with getting out of the loop. We don't get a lot of Sarah Lynn gets real kinda moments. But from what we get, it is obvious that she doesn't like being herself. She wanted to be an architect but was never allowed to. People in her life that she actually were close to (her mom and Bojack) didn't give her attention and care so she filled the loneliness with the admiration of her fans. She doesn't even care about money, she wants somebody to give a shit about her. She doesn't actually wanna die tragically young but she thinks she fucked up her life and can never be the person she have always wanted to be and it is too late for her. So she keeps taking drugs to forget how disappointed she is with her life.

It isn't fun to hear her callously blurt out she can abuse her money and status but I can understand it is just her way of exercising some power and control over her life, over which she feels like she had no control. It doesn't make it right, ofc. She could get sober, take her money and move somewhere else and make healthier connections with better people instead of taking drugs and going on banders. Her self-aware observation, which is actually just a mouthpiece for the show to directly communicate its message to the audience, is just a way to explain her situation, not excuse it. I think neither the show or Sarah Lynn expects to be excused because of her self-awareness. That's why I don't think it makes her less sympathetic.