Do I have the right and obligation to prevent my fiancée from listening to preachers whom I consider untrustworthy, especially since she views this as a lack of trust and control?

A husband must reform his wife and encourage her to observe God's ordinances, based on the verse: (O you who have believed, protect yourselves and your families from a Fire). This is because the shepherd is responsible for his flock. He must teach her matters of her religion with gentleness and kindness, and prevent her from listening to callers of misguidance if she cannot distinguish truth from falsehood, as such listening would harm her religion. However, if she knows the truth, there is no harm in listening to discern the truth and abandon falsehood. He must also protect his wife from misleading whims with gentleness and by suggesting suitable alternatives.