Request for a 成语 to describe a person with all of 貌, 才, and 德 We can use 才貌双全 to describe a person with both 貌 and 才 and 德才兼备 to describe a person with both 才 and 德.

Does there exist a 成语 that describes a person with all of the three?
No, I don't think there is an idiom describing all of the three.

In Chinese, it is very common to use parallelisms, such as "他才貌兼具，德艺双馨".
I used little different terms from yours and parallelize them together to avoid literal duplication.