Andrew LaCivita has some good input on this. He is a career coach and recruitment exec. He talks about negotiating based on the value you bring. A question he often suggests proposing (during and interview or performance review) is:

"I would like to understand: is the amount you offered or are paying based on how you view the position in general, or based on how you feel I specifically do and contribute, based on the skills and experience I bring to the table?"

If they perceive the value of the role as low then there isn't much you can do so maybe you leave. Or you can try to help them understand the role should be valued higher and you can achieve that. If it's based purely on your performance but another person may get more then show them how your performance warrants more and how you are over-achieving to be worth the money you want.

I recommend his videos and podcasts for some great salary negotiation tips.

Thanks for the recommendation will check him out 👍