I think she’d only be slightly worse off than Trump is.
I think people are forgetting how divided the GOP would be, they’d have been tearing themselves apart with recriminations over Trump and the future direction of the party. If it was Kasich or Haley who won the nomination they’d probably win the election quite easily, but I could have seen someone like Cruz or Paul winning the nomination and then throwing it away in the GE.
You do make a good point, but I still don't think it would matter.
Sure, the GOP would probably try to go back to moderating themselves, but the GOP primary voters still wouldn't necessarily reciprocate that ideal. They would still be the deranged, bloodthirsty lunatics that they were in 2016. Someone like Tom Cotton would probably win the primary and, even in spite of how reactionary and divisive he would be, win the general election too. This would mostly be due to what would become massive party fatigue for the Democrats holding the White House, as I said in my post.