I think it is true, the entire GOP is complicit in Trump's corruption. Yes, they're keeping their heads down, trying to stay out of little Donny's ire and tweeting. But by that action, they're putting their own political prospects above the security of the nation; they're violating their oath of office to defend the Constitution. They are complicit by putting their party above national security and the Constitution, party allegiance above the law. And that, to me, is corrupt.
I'm not sure any Republican who spoke out strongly against Trump would get much flak from Democrats. I suspect they'd get a comment about why it took so long, but that's a true observation. They've known Trump's corruption for months, if not 3 years, and were too cowardly to oppose it. I think Democrats would pretty much welcome the support, probably not wholly trusting it, but nevertheless welcome it.
So far the Republicans who are leaving office, not running for re-election, and then speaking mildly against Trump haven't gotten any flak from Democrats. Some gentle flak about how meekly they criticize Trump, but not real flak. At least not compared to the garbage and flak Republicans are throwing at the Democrats on the judicial and intelligence committees taking impeachment testimony.