Ordinary citizens do not try to overthrow the results of a democratic and fair election, even if their guy lost by 7 million votes. Doing so makes them domestic enemies.
And of course there right-wing media echo chamber has to make Kinzinger and Cheney into turncoats or grifters, or call them RINOs. But the reality is, they understand the GOP is pursing authoritarianism, and maybe in 2024 they will have weak willed people in states that vote Democrat, and will try to steal an election.
But you're right, Kinzinger would probably be an independent. And it would probably be the moral thing to do for anyone who actually cares about their oath of office, the constitution and has morals or ethics. Country before party. That's what the GOP did in the 70s when Nixon was about to get impeached. Tricky Dick saw the writing on the wall and resigned (and got a pardon) before anything could happen, because he knew his party would turn on him.
Today, because of the Fox and friends, the GOP has no morals or ethics. They have outrage. They have culture wars. They play a zero sum game that Newt Gingrich pushed. They don't believe in bi-partisan, and see themselves as the true ruling party of America. Roger Ailles famously said that if Fox was around in the 70s, Nixon would never get impeached.