What about a wire straightener like this one?
It's made for the task.
https://www.cabelas.com/shop/en/american-fishing-wire-deluxe-wire-straightener-tool?ds_e=GOOGLE&ds_c=Cabelas|Shopping|PMax|Fishing|HighMargin|NAud|NVol|NMT&gad_source=1&gclid=Cj0KCQjwtsy1BhD7ARIsAHOi4xYcyMWz40llJTuAKIN9nXMPTMEA2Npf4QOJtmdIUoRzOMK-5A8WyMEaAgY-EALw_wcB&gclsrc=aw.ds