In Avengers: Endgame, we see Captain America use
Thor's Hammer, Mjölnir. But not only does he wield it, he also uses Thor's powers of lightning while holding it.
Does this not contradict that
In Thor: Ragnarok, it is explained that the hammer itself is not "the source" of thunder, rather this power comes from Thor himself and the hammer is just a weapon that he can use to control it, but it isn't required.
Therefore, how can Captain America possibly control
thunder by merely wielding Thor's Hammer?