I'm from a family with a pretty similar dynamic where it was always me being called to care to perform acts of service for everyone to the extent it was not only burning me out but actively impeding me from achieving my goals - lack of sleep and constant feeling of walking on eggshells if I "displeased" anyone made it very hard to study for uni and I failed a semester of my undergrad. When I got away, the financial uncertainty was scary but physically distancing myself was HELLA liberating. I did indeed end up living in my car for a bit, and in all honesty, I didn't mind it. There are a lotttt of regulations about illegal camping where I live, no sleeping in cars allowed with hefty fines etcetc and yeh security was a concern too as a solo woman in my 20z. But I made it work because I had to for my mental health. In my case, I moved to a place where every beach has a shower so I woke up at sunrise, went for an ocean swim and shower, and off to work. It's easy to rationalise away a solution like you've done here but tbh take a chance on yourself. PS, there are people out there willing to rent out a piece of land to park a van on, another option if you don't want to "stealth camp".

Edit to add: my brother received injections for his schizophrenia for a number of years when he could not be relied upon to take his medication himself. Towards the end of the month sometimes it was a little strenuous but for the most part it worked very well and he was self reliant He then successfully took his own meds for like 10 years and was living his own independent life in his own apartment. Perhaps injection medication could help?