Postdoctoral Catch-22
This advisor's &quot;negligence&quot; is an act of academic bullying. There is a few things one can do to counter academic bullying, but one has to think them thoroughly well in advance. I'm not writing them here, by now, since some advisors could read them to neutralize counter-bullying.
Maybe you can get some advice from a union representative or someone from your faculty to monitor the situation as an outsider.
Do you have a paper agreement?
Can you write another paper on your own?
If the above does not work, discreetly tell your advisor that you have some work duties from a certain date and that you will not be able to work more on the paper.
After some weeks/days tell your advisor that she is ruining the expectations that this paper is going to be submitted. If she doesn't consider this paper submittable then you can stop wasting the time on it, but you are not giving up coauthorship.
After some weeks/days tell your advisor that you are not going to tolerate any kind of academic bullying or power abuse.