The main thing I notice is some "typical teenager" problems, like not paying much attention to online school, resisting chores and a job, preferring video games over participation in adult life. And then some problems that are -not ordinary teen behavior challenges- like urinating in clothes and starting fires.
I don't think that I, or any non-professional, really, can help you with a 'beyond ordinary teen' stuff very much, but I can give some answer about the less unusual issues that many parents face.
First, I don't think that your daughter will be safe or successful if you just put her out of the house. That seems unproductive, unreasonable and bordering on cruel if she is as unable or unwilling to care for herself as you say. She's going to need extra support to overcome whatever is going on with her, and that means help to resolve whatever is going on medically, a safe home base while she works through it, etc.
What may be reasonable, given her new adulthood (and with the approval of her doctors/therapists), would be to start to have more adult expectations of her. In case, the fact you say she 'refuses' to do chores or work, study, etc, suggests to me that you don't think she's actually unable to do these things, due to mental illness or some sort of disability. I strongly suggest you get a professional opinion stating she's capable of more responsibility but just avoiding it before you start going the 'parenting a typical lazy teen' route with her. If they are on board, and think she can handle some minor challenges, choose some reasonable expectations that you know are achievable, both in terms of physical ability to accomplish the tasks, and ideally something that has natural consequences for failure to attend to it, something you don't have to enforce as it will happen just due to your not being there to constantly rescue her.
Some possible reasonable expectations, and the natural consequences of them, include:
- Do your laundry (or you'll have nothing clean to wear/favorite things won't be clean when you want them)
- Wake up to your alarm without a bunch of parental reminder (or you'll be late)
- Work to make money to pay for your own video gaming subscriptions or supplies (or choose to play free games)
- Clean up your own room and/or bathroom (or it will be dirty)
- Put your cup in the dishwasher when you're done (or your favorite cup, or even ALL the cups!, will be dirty and you'll have to use a different one/wash one out by hand)
- Keep track of your own commitments and appointments (or you will miss them - Apply this only to fun/social engagements, and make sure she makes her needed medical care appointments!)
- Prepare her own meals when you aren't cooking a family meal, or cook for the family on an occasional/routine basis - This can look like anything from making her responsible for dinner one night a week, or telling her Saturday lunch is 'heat your own leftovers or make a sandwich', or just 'everyone fixes their own breakfast in this house'. (Or you will be hungry, have crackers for supper, eat some cold leftovers rather than a hot meal, etc.)
That's not all the possible responsibilities of an 18 year old, but just examples. Choose what makes sense and/or make your own.
The key is to pick things where you know she can succeed if she applies even a relatively minor effort, allow her to do these things in her own way and at her own time, and absolutely avoid rescuing her from the negative outcome of her decisions, even if it's annoying, gross or inconvenient for you. If she does well, recognize her efforts, but not in a 'praising a small child' way, more like you'd acknowledge your spouse for what they do to contribute. If she doesn't do so well and complains to you, empathize with how she's unhappy that her favorite sweater is dirty/her gaming subscription ran out/whatever, but don't solve the problem for her. If she asks you to help, help her do whatever it is, give advice on how to make it easier, encourage her, even stand there with step-by-step support and guidance like you would when teaching a young child to do the chore for the first time, but still don't let her off the hook and do it for her.
This strategy is good for a teen that is willfully not participating in anything that 'feels like work', but may not do a lot if your daughter is actually unable to complete self-care tasks or to self-motivate, for reasons like a cognitive disability, severe depression or ADHD, or if some other disorder is seriously impacting her executive functioning.
If you think this is likely the case, you should start planning in the short term to get her into some occupational therapy, in the mid term to get an adult guardianship of her and disability status, and in the long term for how she will be able to receive appropriate and loving continued care once you are no longer able to support her.