Suppose you are presently under the effects of Magic Jar and are stuck inside your glassy prison. A hostile spellcaster waltzes toward you and casts a spell that does psychic damage, such as Psychic Scream or Wrathful Smite (which does not specify targeting a creature, if that matters). What happens? Do souls have hit points after a fashion? I would think ordinarily souls would be immune to damage, but Psychic seems like the sort of thing that would still work, especially because you're still conscious as a soul in a Magic Jar. Do souls have hit points? Death saves?
In my particular case (if it provides guidance), a player of mine wants to get themselves stuck in a Magic Jar to test the effects of a curse on their soul that does DoT psychic damage when they're not wearing a particular item. Once their soul is in the jar and therefore no longer effectively wearing the protective item though, what happens when the curse starts trying to deal damage?
I'm more looking for a general answer (especially because my players are liable to get themselves disembodied in other ways later in the campaign). Souls may not have a stat block, but there are mechanisms by which they can be destroyed.