Ruffalo's Banner is so dissimilar from his comic-book counterpart at this point that he's practically playing a different character. In Ragnarok and Infinity War, he is - as others have pointed out - nothing but comic relief. Furthermore, in neither movie does he demonstrate his high level of intelligence; he hasn't done so since Marvel's Avengers. However, due to the presumed significant role that the Quantum Realm will play in Endgame, I think that he'll finally again employ his above-average mental faculties therein in order to help the team develop the white and grey/ silver uniforms that we've learned about via leaks.
