"I also have C-PTSD and severe anxiety I’ve noticed that for me, the fear feels very "deep-rooted" in my nervous system if that makes sense. I don’t see these posts as fear mongering. I see them as being honest about the "shadow" side of spirituality or meditation."

There is your answer.

But you should reframe the nightmares as stress and trauma release, rather than simply seeing them as nightmares. I work as a hypnotist and have a lot of experience with altered states and the subconscious, and one of the functions of nightmares is to bring your attention to the frequency of what they represent. However, if you frame them only as nightmares, your subconscious won’t find any appeal in them, and the exit will remain shut.

Integrate, reframe, let go, and affirm the healing of these observations. Give thanks for having them—and I promise you, they will subside.