It sounds like life is really tough but like many things in life this is probably a phase.
My eldest, now 22, is autistic - fortunately diagnosed very young. Parenting has had many challenges and a hell of a lot of self reflection and exhaustion.
One of the best and most direct bits of advice I received from a psychologist was if giving 100% of yourself isn't enough why not give 80% and take back control of 20% to focus on yourself and the rest of your family.
When you take more time to step away, its easier to deal with the day to day.
It sounds like there are an awful lot of little things that have escalated to feel overwhelming. No doubt from what you say, your daughter is also completely overwhelmed.
Trying to tackle all the issues at once would be a massive overload, if she is on the spectrum, and already showing signs of being overwhelmed.
So my thoughts would be start by writing down everything that isn't right with the situation. Then right down every aspiration you feel your daughter has expressed in the last few years.
What you no doubt want, like the rest of us trying to find our way through this life with no user guide, is for your daughter to grow up to be a strong independent adult. What she no doubt ultimately wants is to have control too - but if overwhelmed that concept maybe too big to cope with at present.
The next issue is to choose just one area that you'd like your daughter to work on for the household and one to move her forwards in life towards those aspirations.
This could be open windows to ventilate room for 30 minutes a day, only eat cold foods upstairs and take all dishes downstairs once every 24 hours. It is okay to express this is because you recognise she has a right to her space but she doesn't have a right for her actions to have a significant impact on the rest of the house - strong smells of stale cooked food have this impact so this is a respectful boundary and compromise.
The move forwards could be sit in the back garden and get 20 minutes of fresh air in the sunshine - building up to walking round the block or going to the local shop to buy x, y, z twice a week. I'm guessing your DD has a reasonable IQ because you mention A levels. You could link to Instagram able type articles on the benefits of taking daily short walks for mental health.
I find communication over whatsapp. Simple instructions and encouragement is less contentious than direct verbal. The first steps forwards need to enable her to have control, not be overwhelming, but also to express that the current situation doesn't work for either of you and your desire is for her life success. If she's feeling very overwhelmed even backed into a corner, she may not recognise that's your aim.
Sometimes baby steps, reopening communication backed by reassurance that you're there can produce results.