Incumbents coast to reelection in most races - unless they are a Republican with a backbone, because that's the biggest turnoff for Republican primary voters nowadays. Cheney did rise quickly in the Republican House hierarchy before Trump happened though - which, whatever else you may think about that, does show firstly that she's a talented politician irrespective of her last name (name recognition may help you get media and voter attention in primaries, but it doesn't get you any positions voted on by members of Congress), and secondly that she had a lot to lose by refusing to kowtow to Trump.
I think liberals and the left-wing media have made it pretty clear that they haven't forgotten about Cheney's conservatism in general, nor about the thing with her sister specifically. Nobody is saying they love everything about her - but in a party where nearly everybody else has thrown their principles out of the window and fallen over themselves to lick Trump's heels so blatantly, I guess someone who hasn't does stand out, yes.
Who cares? Her opponent is just another Trump bot who intends to build a career on pretending not to have a single original thought in her head, whether or not she actually does (so far, my impression is that MTG is the only one who actually IS that clueless, rather than just pretending to be for political gain, but I could be wrong, it's hard to tell).
I certainly agree that it's insane that she stands out as much as she does among Republicans in the House, considering the extremely low bar she has cleared. But sadly she does, so she gets the media attention that goes with it.