There are two types of ways of a character being "strong" with there powers. POWER Creep and POWER Mastery.
Power Creep is when the character gets objectively better stats and grows ability( IE getting a new form or grow a new superpower.)
Power Mastery is when the character has the same powers that don't change but they find new ways to use them ( such as using Josuke from JOJO part 4 and the many uses of his one "healing" ability"
Soul and Marcel have power creep.
Asta and Aclava have power mastery.
But most importantly, Chris has both, he has a powerup mode and can use his newly given powers more and more ways. That's what makes him so powerful.