It's Endgame. Instead of Mjolnir for Cap, the Scarlet Witch summons a magic sword for Cap - which he is fully able to use. Negative side effects not an issue in the fight.
Pick a sword or suggest one that might might a difference and a quick takedown. I'll make two suggestions:
1. Tessaiga
2. Stormbringer
Results for these and others? Here's some: https://en.wikipedia.org/wiki/Magic_sword