A troubled young woman, tying to outrun an oppressive past, flees to the outback, only to find herself in the way of an ancient malevolent spirit awakened by a thirst for revenge and hell bent on destruction.

What does "...oppressed..." mean in specific and visual terms? How is it relevant to the plot of defeating the monster?

This logline is vague and confusing, mostly as a result of it lacking a clear plot and motivation. I suggest reveres engineering the logline from the goal. What specifically does the MC need to achieve by the end of the story?

As Richiev suggests, option 2 seems to be the better approach.

An oppressed woman runs from her past only to find she must stop a vengeful spirit before it destroys everything in its path.

If the past is important to the story then it is important to the logline. For instance if, ?in the past, your mild mannered family man was a mob hitman... now bad guys have come to town and his past becomes relevant to the story, then it needs to be in the logline

However I am not use how the abusive past will be relevant to stopping an evil spirit...

As a result you should do one of two things,

1: ?Add to the logline how her past is relevant to the story...
or
2: Remove the beginning part of the logline and focus on what she must do to stop the spirit and leave her backstory for the script.

I believe either will improve the logline.