I mean, there's many ways for her to defeat the predator, as long as it feels earned, and that we feel she has gone through A LOT in the movie in order to succeed.
On a side note though, it is more complicated for her compared to Dutch to pull off some specific tricks, like the decisive big log trap, which he was able to do only with his physical strength.
So I think worrying about the fact that she could defeat a predator in a believable way is not an entirely invalid point either, I'm just staying on the optimistic side of things.
Also, at 1:53 in the trailer, it looks like there's a head or some body part attached to the spear when it hits the tree