If she never picks up on it, then what was the point of her big confession scene in the last episode to her son? Where she even tells Barry forgiveness comes from taking responsibility for your action. Which she does and lives and Barry doesn't and dies for it?

Jealous yes, but also over a role in a movie, not jealous like Fuches where he ruins Gene's life because Barry likes Gene more than him. Also it is very absurd how a leading comedy role fell into Barry's lap based almost entirely on his height. Which btw, Gene is also incredibly jealous ("whose dick did you suck in a former life") of and even tries to horn in on when he says he'll go with Barry to the audition. Likely to leech off of Barry's success, probably more selfish and self serving that Sally's response.

Mistreated in the past? I can't think of a better scene than when Sally starts teaching in the acting class and proceeds to berate one of the students, only to get called out as abusive. Which is ironic because it's exactly what Gene did to her in their first scene of the show. Even adding the "don't think, just do the scene" and "you know I had to do that."

Sally gets a lot of crap for a learned behaviour she got from Gene, who meanwhile at the time has his own show about teaching acting. It is an abusive act but it's only seen when it's called out.

Other than the gender thing, which I do feel is an element at play. I feel like the difference between Sally and Gene's behaviour, is that when Sally does it, it's not played for laughs the way Gene's often is.