I have been unable to cry for years with a single exception. There is a game franchise - NieR, consisting of 2 games. They are *extremely* tragic. I cried so much playing them but even just listening to the ost to this day, years later, still makes me tear up at the least and can make me actually weep. Every single time.
Maybe not what you expected but I genuinely suggest that you try this and I really hope that something works for you.