Just because she was burned by the Bishop, doesn’t mean she didn’t keep her Catholic faith until the very end. She was a devout Catholic, it was tragic she was thought a heretic by the church’s bishop when she very clearly wasn’'t and was exceptionally devout to Catholocism to the point of dying in her belief she had been visited by St Catherine. She died for her own Catholic Faith and in faith she had been visited and could not lie about it and was killed by a catholic bishop who didn’t believe her.
This is far from protestant, she did not protest against the church, she upheld it’s beliefs to the utmost, honestly believed she had been visited, and could not lie about it even when the church came against her itself and put pressure on her to refuse she had been visited. She literally could not give up faith in the Catholic belief system, even when the human beings running her church tried to get her to go against her own belief and admit she was lying.
There is difference between refusing to give up faith in the Catholic beliefs(and the church), and becoming a protestant against the Catholic beliefs. She did not give up belief in the Church, it gave up belief in her then realized years later it had made a grave error in judgment and had made a martyr of one of it’s most devout followers.
