How to leave a toxic friendship?

I’ll try to condense this as much as possible.

I (23F) have a friend Kate (24F) who Ive known for a very long time. We’ve been close friends for about 5 years, I would’ve even called her my best friend a few years ago.

Ive been going to therapy and Ive realised our friendship is really toxic and imbalanced. In the span of the last 5 years which coincides with us being close friends, Ive become a registered nurse, have graduated university, moved away, have a long term relationship, and have started travelling. Our friendship began with us smoking weed a lot together, talking about our mental health, doing other assorted drugs occasionally, all stuff that I’ve grown out of thankfully.
Kate has not. Kate is a habitual stoner, I don’t judge stoners because I was one myself, but i feel it’s important for context. She pretty much smokes weed all day, works casually at a pub, doesn’t have a license because of fines, and Ive always supported her because I know she’s smart and I wanted to believe she could turn it around.

Kate hasn’t ever really been the best friend to me.
She moved away recently too, about 4 hours away, which Ive gone to visit her 3 times on my seldom days off and have stayed with her for 2-3 days at a time.

She lives with her dad. Each time i visit, her house is literal squalor, like it’s completely filthy. There’s dog poo in the house, dog pee, dead insects, spiders, old garbage, dirty bongs, dirty clothes. When I go to stay with her, I’ll sleep in her room, and when I fall asleep she’ll get on discord with her other friends and play games right across from me and will wake me up multiple times by screaming on the game. Last time I was there, she facetimed a guy that wasn’t her boyfriend ALL. NIGHT. I had to ASK her to get off the phone in the morning so we could go do something together. In my opinion that’s basically cheating but it’s not my relationship so I don’t want to get involved. This is after I drove 4 hours to see her, BTW.

Everytime something big or exciting happens for me, I can never share this with her, because she glazes over it and begins to talk about herself.
I recently went to Thailand, she didn’t ask me how it was or if I enjoyed it. I told her I was going to Vietnam next year and she blatantly ignored it.
Everytime she does ask how I am, which is extremely rare, she makes it about herself.

In the past, even the not so distant past, she’s asked me for money, to pay rent for her family, to move into my house, to pay for petrol, to pay for things. Some of these things, like petrol and concert tickets, I have paid for, with the agreement she will pay me back. But she has never paid me back for any of this stuff, not the $200 concert tickets from this year, not the $150 concert tickets from last year, not anything. It has always bugged me but I’ve let it slide.

Sometimes, when I see her, I’ll let her drive my car because her car is out of service. She constantly criticises every single thing about my car, points out what needs repairing, talks about how she would’ve picked something different. This is someone who doesn’t even have a working car. But I just bite my tongue, every single time.

She recently had an unplanned pregnancy, and hinted at me giving her money to pay for her abortion, which I didn’t. She then dragged her dad through the mud because he wouldn’t pay for her fucking abortion, calling him selfish.

I’ve just realised recently, I can’t do this anymore.
I don’t want to be friends with this person. She doesn’t give a single shit about me but I don’t know how to untangle myself from this. She messages me on Snapchat every single day and recently I haven’t been responding. She’s noticed and is getting saltier and bitchier by the day. I don’t want to be her friend. But I don’t feel I owe her an explanation because I know she won’t take accountability because she never does with anything, so why would she with me?

How can I end this without a confrontation? Does anyone have any advice. Also, I’m I focusing too much on the bad? We do have some good times and laughs together. I don’t know if I should leave this or if I should just keep her at arm’s length. It feels kind of shitty to myself to continue having this friend in my life. Any advice is appreciated in this situation.

TLDR: My friend is lazy, unbothered and not emotionally invested in our friendship. It feels very imbalanced. It’s not serving me anymore, it drains me mentally and physically. We have a long history and I’m scared to walk away. Not sure how to go about this, any advice is appreciated.