Dispel magic has a particular purpose: to break other spells. It has no effect on a vampire's Charm ability or any other magical effect that isn't a spell. It also does nothing to the properties of a magic item. It can, however, end a spell cast from a magic item or from another source.

How do you dispel in magic 5e?

Dispel Magic per the PHB: Choose one creature, object, or magical effect within range. Any spell of 3rd level or lower on the target ends. For each spell of 4th level or higher on the target, make an ability check using your spellcasting ability.

Does dispel magic work on multiple spells at once?

Dispel Magic removes all 3rd level effects on the target.

Every spell of 3rd level or lower on the target ends. The effects of the same spell cast multiple times don't combine, however.