Step parenting

I am a step mom to 2 teenagers. (I have no children of my own but have helped raise my nephews and niece)
Bio mom is dead from a drug overdose and was never really present or big part of the girls lives. My husband has had full custody since they divorced 12 years ago. My husband and I have Been married 2 1/2 years.
The youngest (15) and I have a great relationship. Beyond typical teenage attitude issues here and there, we are very close.
Long story short, the oldest one (17) absolutely hates me and has told me several times her greatest wish is for me to be out of her life. She has been physically violent towards me- police came and talked to her for 2 hours. She was in therapy until Covid, But honestly she manipulates everyone and told the therapist just what the therapist want to hear. She is very intelligent lies all the time.
My problem is, my husband seems to take her side on a lot of things and rarely does anything to correct her. He never follows through on punishments.
Any advice? I am at a loss. I have never dealt with anyone so manipulative and narcissistic.

She is on medication which does help some. I am also on antidepressant/anxiety medication

That is a really tough situation and I’m sorry that you have to deal with it all. It is really unfortunate that your husband isn’t supporting you with this situation - and at 17 she is no doubt a challenge.
I would in no way pretend to know the answers but I can offer a couple of ideas - you may have already thought of them.
You may want to ask her therapist if you can join her for some sessions - she obviously has a lot of anger from everything she has dealt with and you are the easiest target.
Have you and your husband considered couples counseling to deal with what is going on - a lot of men have an aversion to therapy but it doesn’t mean you are broken, it just means you want to be stronger and it can really help with the communication and consistency. It is possible that hearing it from someone else and realizing the damage that is being done may finally reach him.
I totally understand the depression as I have lived with it my entire life. It took me a very long time to get to where I had a grip on it - although I still have rough days - so give yourself some slack.
I would highly encourage you and your husband to come up with a list of rules and consequences for breaking them - and make sure that he stays accountable for them as well.
One last thought - rather than call yourself a step-mom, try to consider yourself a bonus mom with bonus daughters.
Again, just a few ideas.

Wow. Your words of wisdom and encouragement truly feels like words from God. To say thank you seems so trite, but thank you for being the mouthpiece (or typist as the case may be) from a higher power. You are truly a blessing.

@Katie_Davidson Katie, Thank you is never trite and you are very welcome. If there is ever a time you need to vent or ask a question or just need a shoulder to lean on - please do not hesitate. I’ll never be rich or famous, but I do believe that God put me on this earth to be there for others - and help if I can - know that you don’t ever have to be alone in your tough times - I’m never too far away (but not in a creepy way)