Charming and charismatic aren't necessarily one and the same. They can be, but sometimes a charming person isn't always charismatic and vice versa.
To me charming is more warm and intimate. A charming character plucks at the heartstrings of whoever finds them charming and pulls them in onto an intimate plane. But some stock traits of a lot of mainstream-deemed charmers are that they are easy to talk with, they generally have a light way about them, and aren't guarded with either their words or body language. A textbook example would be Matthew McConaughey.
Charisma, on the other hand reaches a wider swatch of people and is often tied to leadership. With their charisma, they can affect people to respect them, think highly of them, or venerate them. One trait that I don't think you can be charismatic without is confidence. And to an extent, some level of intelligence, either book smart or street smart.
Like you can be charmed by a bumbling fool because oh, they just try so hard and their heart's in the right place and they're just so genuine and good, but they aren't charismatic in the least. And you can find someone charismatic by the way they speak with authority and how easily they interact with others, but you might not find them delightful to be around.