You make an interesting observation. There is no way you’re ever going to get Republicans to agree upon a single candidate. Trying to control Republicans is like herding cats. I’ve seen it up close. You do not tell Republicans what they are going to do.
The problem is there are too many different republicans. There’s only ond kind of democrat. Followers. Republicans actually think. I think the only answer is a third party. The big tent thing collapses every time.