PhD supervisors: NOT your friends
Some fraction of PhD students probably knew that during start of PhD, vast majority didn’t. PhD supervisor is an adult person with her own self-interest. In her scheme of things low paid slaves for an unlimited amount of time really works out. From your perspective (should have been), it’s a train-wreck for the whole time. Since about 50% PhDs go for postdoc, message hasn’t really gone through.
Slavery and low confidence and poverty doesn’t make you a great scientist, it makes you a pathetic loser. Since there are no jobs to vie for in academia and it’s a hindrance to get a real job, quit as fast as you can.