OP I've just read your thread and it sounds awful
I agree with others that you need to step back from this but I understand why you can't.
My best friend since primary school moved in with me when we were in our late 20s. All great for the first month then she started acted strange and locking herself in her room. I did everything I could think of-cooked for her, rented her favourite films (blockbuster days), checked she was ok, offered to do her shopping... I got silence.
Then one day I came home to find all her stuff was gone and she left about a three line note accusing me of mental abuse throughout our friendship, saying how awful I was and she was better off without me.
I was distraught and tried to get in contact with her through family but she changed her number and told them all these horrible lies.
I found she'd also told mutual friends these lies-and I'm talking accusing me of things like locking her in her room without food and water (🤯) but they immediately saw it for what it was and sided with me.
What I'm getting at is that it took me about a year to really let it go. And I realised it wasn't because I missed her-she wasn't the friend I thought she was. But it was the INJUSTICE of it all! I wanted vindicating and for her to admit that I'd done nothing wrong. I wanted to be proved innocent. I wanted an apology ... an explanation or anything!
Then I let it go. I realised that she obviously truly believed these things about me and if that was the case then she'd constructed a pretty toxic narrative of our friendship and no amount of persuading was going to make her change it
It's the best thing I did and I'm so much happier. I think you do need to try and let go too