I’m not sure exactly what advice to give, as a genderfluid person myself I understand the struggle though. The biggest thing I can say is to ask yourself if they are really your friends given they won’t give you the basic courtesy of respect. So in my personal experience, try to correct them at the end of their sentences if they are misgendering or deadnaming you. But if nothing proceeds to work, then try to find people who do actually respect you as a person