I have a rare sensitivity to magnesium. My kidney & liver functions are fine but my body holds mg causing dangerously severe symptoms at NORMAL blood levels. I have to go to the emergency room with the symptoms which confuses the heck out of their "textbook knowledge"! People like me exist! I function perfectly on low mg.
It may help for you to take all you've learned here and add your own hypomagnesium & hyper magnesium findings. I hope this posting finds you well.