Trump backed candidates are doomed to fail in all but the most MAGA of districts because, well, they aren't Trump himself. Trump has a combination of charisma and teflon to be able to say crazy stuff, and his supporters just love him all the more. But put that rhetoric in a non-Trump body and, well, it's just wackadoodle talk. No reasonable populace is going to elect somebody to lead them on a platform of "the election iz rigged%$@!". People want governance at the end of the day.
I watched it happen in AZ last election. The magawhackier the candidate, the worse they lost.