11 yr old ASD daughter displaying controlling, obsessive behaviors w/explosive violent outburst for hours

Hello, I am Kory, a mother to an 11 year old daughter with ASD, diagnosed when she was 8 years old.   I apologize in advance for how lengthy this post is.  

Short issue - she seems to have become obsessed or controlling, or trying to be and has started to go into unexpected or triggered (or so it seems) violent aggressive rages where she destroys things and throws them, screams, yells strings of cuss words while crying loudly and banging on walls etc.  Does anyone in here have any experience with this personally as an individual displaying the outbursts or a parent or caregiver at the receiving end.  I am trying to understand her but she will not discuss anything about it, when asked she stares blankly at me like I am not speaking to her, but will then start talking about something a kid at school did that day.

She has always been quick to frustration and violent outbursts where she would throw anything within reach and hit herself in the head repeatedly, even if she was holding something, and bite her right forearm and leave complete teeth marks indented in her skin which would stay for a while.  I discovered pretty quick she was not displaying these behaviors in school or daycare, where I learned she was masking pretty good most the time.  So at home where she was comfortable she let down and her older brother (with ADHD and ODD diagnosis) would mess with her when he was bored bringing on full on autistic tantrum for hours where I would have to sit with her in a bear hug and try to keep her from destroying things, hurting herself or others. 

Eventually I educated myself and started learning the signs and triggers and ways to help her and spot when she was about to have a meltdown and she started to have less frequent outbursts.  I would try to not let her get too tired or hungry because that would add to it. 

Her brother moved out about a year and a half ago and it was pretty peaceful and calm at home with rare full on outbursts or violent fits until about 8 months ago.

A bit of background - I have been dating a man for almost four years and we had a routine of him coming over one or two nights a week when I had my children for dinner and spend some time. She was always excited to answer the door and would be happy but didn't interact much or care to stay downstairs with us after dinner.  She would do what was needed and shower, go to bed at her bedtime without much issue.  On a side note, he never has stayed the night when my kids were here, they go to their fathers Wednesdays and every other weekend. We would spend more time during those times.  

About 8 months ago she seems to have just flipped, and all of sudden without any sign or warning she felt any differently him coming over she answered the door one evening, immediately started to yell, cuss, violently throw anything she could at him and demand he leave her house.  She takes it to the extreme where she will destroy anything close, put holes in the wall, throw anything near and will cry and scream and be aggressive continuously for consecutive hours.  So far she has gone as long as 5 hours in that state.

That has happened about 6 times where he seems to be a trigger and she has escalated it to other things like when asking her to do her chores like empty the dishwasher or when she has been told no when she asks for something.  She has gone into a fit of rage in retail store, in my vehicle while driving and has hit me and cussed and thrown things.  She seems to try to make things look like I am doing something to her, she will get out in the cold with no coat on and then beat on the door or windows for me to let her in and she could get back in as they weren't locked and I would be trying to ignore the angry fit and just be casually looking at my phone etc.  

I have had to call the police for assistance and she has been taken the emergency room where we are told there are no pediatric services and what is it I want from them.  Where we live the county doesn't have crisis intervention or places for pediatrics.  So basically have racked up $2000 bill for her to sleep and be talked down to by a psychiatrist thru a teledoc system.  When i have spoken to her doctor or teachers/counselor at school to see if she has changed in her behaviors there a bit they all look at me like, poor overstressed mother, and tell me what I basically already would know that she wasn't displaying those behaviors there.

When she is asked why she abruptly changed she used to be non-verbal, now she will just say it is a secret or she doesn't like him but wont say why.  She will not tell anyone else what she is doing or acknowledge how she is behaving to others and when we saw her neurologist and I asked her if she wanted to explain what has been going on or how she was feeling she said happily with a smile, "no you can tell her".  

She displays aggression and harasses him when we see him at the gym and will watch us talk through the glass in the childcare area into the gym with a look of what I can only describe as a crazy jealous ex-lover or something of that nature.  She has gotten increasingly more controlling, or has tried, and seemingly obsessed with who I talk to or if someone coming over, which she does not want.  

This is obviously a strain on my relationship and a big worry on me for many reasons.  I used to think something was happening to her or someone was doing something, then that moved on to did he do anything but was quickly ruled out because they haven't ever been alone together unless I went to the restroom, so then I worried was it on set symptoms of psychosis of some kind or schizophrenia as it presents in females about this time and she is in the second stage of puberty.

She started out not very social with other kids and she attended a pre-school part-time (after a referral from First Steps program) for children with physical and mental disabilities/challenges.  We discovered she was behind cognitively by a year and a half and she would not engage at all with other children, not even parallel play.   

Bit more background - 

She was born with a genetic deletion, called interstitial microdeletion of the 5th chromosome, 2 & 3 genes.  (since her birth we have learned she has 2nd/3rd degree AV blockage, non-compaction cardiomyopathy of the left ventricle and an unnamed rare SIDS like condition,  (potential for a pacemaker at some point) learning disabilities, muscle strength & tone issues and the most recent ASD diagnosis).   She displayed autistic symptoms early on and was fairly obvious but took me years to get the referral for an assessment which happened right at the onset of COVID but once things reopened we were the first to have it completed.