I'm sorry to hear that you haven't gotten much help. I did find this research type of article that provides more information and might offer some insight that helps.

-- Management of nightmares in patients with posttraumatic stress disorder: current perspectives: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6263296/

The Veterans Administration also has some information that may be helpful --- PTSD nightmares: Is there an effective treatment?: https://www.research.va.gov/currents/0319-PTSD-nightmares.cfm

If you don't mind sharing, is your PTSD related to trauma of some sort?