She is not a good character, she has no redeeming qualities. I’m not talking about the actress, but Reva the character is a failure at everything.
Her motivation was revenge on Vader/Anakin, which she waited decades to achieve and had virtually no plan to achieve it. We clearly see that she is willing to hurt innocent people and children, so she isn’t sympathetic to those people (which is fine, evil villains are the best). So, she isn’t trying to stop the Empire, just kill Vader, which again is fine, vengeance is a reasonable motivation for an evil character, but her “plan” is awful and makes no sense.
She doesn’t try to trap Vader or set him up where she has some kind of great advantage, she ultimately just tells him she hates him and he beats her horribly. But Vader is a true Sith. He seeks challenges to test his skills against. If she had simply challenged him he would have accepted and the results would have been exactly the same, which makes her motivation for her actions and her role in the show pointless. She wasted all that time and was just an idiot. Then, somehow she is still alive, and seeks Luke? But doesn’t kill him because now she is redeemed? Maybe? How? Why? There is no reason to think she hasn’t slain force sensitive children in the past, there is no reason to think her desire for vengeance has been satisfied, and there is no great epiphany she has to face, other than Vader is much stronger than she will ever be in a straight fight to change her outlook on life. Her character should have been looking for an edge. Her only goal after hear that plot convenient message should have been to use Luke as bait to set Vader up in a position to blow his ship up, or something where she can try to kill him from a distance. Big bomb or something.
I don’t know if she is supposed to be redeemed by the end, I was waiting for her “plan” to have some kind of payoff, or for her to be shown as actively working against the Inquisitors the whole time, or something intelligent, but we didn’t get that. Just a dumb character doing dumb things.