Luther wanted to reform Catholicism not 'fight it'. Protestant literally comes from the word protest. Catholics in protest.

He never wanted another church schism, but it happened anyway. Also hard to call him the 'founder' of protestantism when

1: There were people before him with the same complaints like John Wycliffe and Jan Hus. The former inspired the later and both inspired Luther.

2: The protestants immediately fractured, during Luther's lifetime. It got bad enough for Lutherans, Calvinists and to a lesser extent Anabaptists to kill each other. Mostly because Zwingli called Luther a cannibal lol