The Republicans opened their legs for Trump a long time ago. They crossed the moral event horizon when he was shown to be unfit for office and a traitor, and they cheered him on.
So when you say they cannot deny the facts about Trump's conduct--I'm afraid that yes, they can, and they will. I do think that everybody understands that all the purple-in-the-face outrage they're expressing is just for show, and what the Republican congresspersons and senators have been doing is putting on a show for an audience of one--the Orange Asshole.
I doubt very much that there will be more than a very, very few Republican voters who will be so disgusted for Trump that they listen to their consciences and don't vote for him. Party loyalty is all that seems to matter to them. It really doesn't matter what Trump does or may have done. The "base" will never abandon him.
He may lose the 2020 election--after all, he lost massively in the popular vote and only a series of extremely narrow fluke victories gave him the Electoral College win. So flipping even 1% of the population may make a difference. The "base" is beyond redemption--but the Democrats have to gather in those voters who still have souls even though they voted for Trump last time.