Leave If you’re unhappy with her choices. Doesn’t sound as though she is willing to give up her “only device” which is BS by the way. As for her saying she isn’t addicted, well that’s not uncommon for addicts to state this! It’s called denial! Avoidance or whatever viewpoint you want to call it.
You are not in control of her life but you are in control of your own, so make some decisions about what YOU want. If this is affecting you as badly as you say then it’s time to walk away and live a life free from something you dislike! Let her go and smoke her tree and get on with it. It will only destroy her in the end!