Relationship Advice Regarding Love/Wisdom STS/STO

[Ohr Ein Sof]

the point of unprovoked physical assault and destruction of property that she justifies in her own view as being necessary.  She also greatly uses emotional manipulation in the form of guilt, self pity and victim mentality to emotionally get us to bend to her will.

That sounds like an unconscious inner struggle with materialism.
But i think this is only a symptom of an other deeper problem.

I guess the main concern I have is the polarity issue in that I feel guilty for enjoying this emotional relief and freedom from her.  I worry that if I contact her, nothing will change and I'll be pulled back into her behavior but I also don't want to lose a parent and I see that her behavior stems from deep pain and trauma and I honestly don't know if she is fully aware of what she is doing to herself and those around her.

It seems that you have only the choice to fulfill her control or keep your freedom.
So your last conclusion is correct and you must decide how to handle this catalyst.

From my experience there is no really decision possible, because you have to decide between the feelings to your mother and fulfilling the will of someone else (STS).
The logic choice for a being in STO is to accept that you can't be in STO by fulfilling STS.

I do not think it is fair to bring STS and STO into a discussion which clearly is surrounded by confusion, mental confusion which is due to trauma.

This is a very difficult subject because this is a trauma that is being replicated and being passed from mother to child. Living with a narcissist can literally be a living hell and will likely injure the entire family. Generally speaking, it is a generational mental/emotional disorder. The narcissist gets worse over time as the narcissist sees that the children are growing up and getting ready to leave the home or have left the home and so they need to maintain a strong level of control at a distance. The healing involved for the children can take literal years of work while they uncover one trauma at a time. So, with that being said...perhaps you are to consider yourself and your personal mental health. Having her gone for a moment has given you all a much needed break. The stress the entire family has been under due to her illness has been no doubt great. Perhaps you could take this much needed time and do some self discovery? Ask yourself, why not have a small break? It does not mean you do not love her and worry for her. She is an adult and trust me, she is fine. They have no intention of self harm if she is a true narcissist. She will be back in one form or another. Please consider your guilt for wanting this time of rest and quiet.
Living with someone like this distorts our thinking and clouds our judgement. Our thoughts will be forever turned toward what the narcissist wants and needs and we will continually forget about our own needs. This leads to us feeling very unworthy of anything that would considered to be "deserving" like love, care, rest and even something simple like eating. This is time that your family has been gifted to you. Hopefully you can see it this way.
-much love