Oh, no, they'll devolve into infighting. There won't be enough shared ideals and actions to sustain Republicans as a political force. There will be fringe groups that linger on for a while. After almost three centuries, there are still two people left claiming the Shaker tradition; that's a group that forbids sexual relations even for procreation, so you can see how they'd have trouble gaining new members. But they're not a religious group that anyone really cares about, either. That's how MAGA will go eventually.

See also, Knitting Cat Lady, who is a former member of the Children of God cult, then the US Army, and then got a masters in organizational psychology around cults.