Jabs are probes to find weak spots. Knowing weak spots gives her a feeling of control and so will reuse them when she feels threatened or cornered.
Reacting to jabs is letting her know it is a vulnerable area. We all have vulnerable areas. It does no good at all to announce them, even in calmer times. Once they are known in a dysregulation they will be used.
If it is something that digs too deep then it needs a strong boundary where you pull the plug on interaction at that point. There needs to be no push back reaction.
Your method is to be clear in your own mind what you need a boundary about, and what you can let go.
But where is the line. My line is don't say hurtful things. Don't be purposefully mean. If you offend me unwittingly apologize. I expect to be treated with dignity and respect.
Rephrase this, it is worded as a demand not a boundary.
Demands>require her action
Boundaries>require your action
>>I will not stay and listen to hurtful things, be treated meanly or treated disrespectfullyThough this might be still a bit too high a benchmark to start with
Dont tell her how to behave show her how you respond to certain behaviors, without arguing about it