"an unequivocal mindfuck"
Please see sleep lab studies and research the extint to which they are suddenly being utilized by neurologists who would likely refer you to a psychiatrist were you to mention your experience. There is always the alternate or contributory diagnosis of psychosomatic illness.
Learn about the current level of neuroscience and brain imaging. Lucid dreaming is natural, as is the hypnogogic (I believe that was the previous medical term for waking without the ability to move following a dream state.) My own were previously experienced as the "dark man" about to enter my home and my need to wake and protect myself, but upon waking, I would find myself unable to move. That is the "psyche" or the unconscious telling us that we have unresolved issues, threats, or fears which we are attempting to suppress on the conscious level.
The experience you have related in the initial post as your most current level of experience during sleep paralysis, presents in a manner consistent with my own current inability to dream and allow the unconscious levels of the brain to process during natural REM. I do not dream, rather I experience fabrications of dream states that suggest virtual states of experience, and as a result I do not experience REM nor do I wake "refreshed" or feeling the natural result of having experienced a state of "restful" sleep. 8 hours or more...no sense of having "rested".
There is a slight difference between a persons belief system and scientific rationality. There is a very high change that the person concerning themselves with sleep paralysis really does need to check into it further through equipment and testing that can only be provided by real doctors.
I don't want to propagate a source of worry to them or make it seem worse than it is, but it could be a number of worrying things ranging from a genetic disorder right through to tumours or it could be something as trivial as drinking too much caffeine during the day, however that's the problem with online diagnosis or theorum's in regards to effects.
For them to rule out the "Worst case scenarios" it requires true diagnosis, not just someone stating that "Lucid dreaming" is natural or what ways to achieve better control over how you influence such a state.