I would say that her problem is very different than Hillary’s. Hillary was not popular with Democrats and she was hated by Republicans. AOC is loved by some Democrats, liked by a bunch, and disliked by some while being absolutely reviled by Republicans. That would get AOC more support than Hillary got.
It’s the “absolutely reviled by Republicans” part that is the concern. It doesn’t matter how popular she is with Democrats. It matters how popular she is in the swing states, and whether she can be competitive in a red one.
Mark Kelly can win the swing states; AOC and Hillary cannot.
I’m not familiar with how popular she is or is not among unaffiliated voters. That matters more than how Republicans feel about her.
Many of the people you call “unaffiliated” most recently voted Republican, and refer to themselves as Republicans. When I speak of “Republican” voters, I mean the people who currently intend to vote for Trump, but would be willing to switch for the right candidate. You would probably call that group “unaffiliated”.
