The established, do nothing Republican Party hated Trump. He refused to be a Washington insider that would cave to the DC lobbies. They couldn't stand that he took his direction from the people outside of Washington. So, as much as the Democrats hated Trump, the RINO's hated him equally.
It took Trump years to get control of the Republican Party, now he's there.
The old Republican party is gone, after the inter-party war, and a much broader coalition has formed, including blacks, hispanics and Jews. That's MAGA. Now you are seeing the Democrats, go through their own inter-party war, where their coaltion has totally melted down.