The GOP never embraced Trump. Liz Chaney and her ilk are scared because so many voters see the GOP for the scum that they are. Trump was elected because he acknowledged how poorly government serves the people. The Tea Party brought this to public attention years ago. Trump was an extension of that attitude. His success scares the hell out of the establishment GOP who are only in it for themselves.
Why did Liz vote to impeach Trump? Because Trump is an outsider. He didn't run for office to fatten his own purse, he ran to serve the USA. Such outrageous patriotism cannot be tolerated by the party.
I agree with about 90% of your post. Here's where we disagree:
1. 74m voted for Trump, that includes the "real grassroots GOP". The GOP "establishment wing" including "Never-Trumpers" (all ~100 of them) hate Trump, because he was so successful, and they suck.
2. No voters see the GOP as scum, the GOP did not lose one House seat in 2020, so you are just plain wrong. Reality is that the democrats lost House seats, and will lose the House in the 2022 mid-terms.
3. We agree why Liz voted to impeach Trump, which is why Mitt and the other senators voted that the impeachment was constitutional, when it isn't. Because GOP voters now expect results, like Trump's "promises kept" list:
Record-setting first two years
welovetrump.com