The theology may have evolved, but to say they were never Christians would be unjustified, even if I agreed they had stopped being Christians due to this.
I do however not think that is the case either. I agree that their veneration for Trump often becomes pretty much worship. That however doesn’t mean they aren’t Christian. He seems to take a status in their theology ranging from a saint-like figure to prophet and even the second coming of Jesus. Christians started out as a jewish sect and only over time became a distinct religion. I think this Trump worship is similarly a Christian sect that could potentially become a destinct religion. I just haven’t been convinced it has happened yet.