I also got my PhD in a similar system. Had my own funding for four years and then it was up to me and how much I was favored by my advisor. The scholarship was already tax free, couldn't offer pension rights. So I wasn't able to apply for unemployment fee later. Same thing happens for postdoc too. There are people offered contracts but usually they find a way to make it a stipend. I even came across PIs telling "you need to volunteer for free" to stay in academia. They make it sound like you need to give up on everything for your passion, dream etc. If one can't cover up their daily expenses they can't focus on an article or experiment, those become very abstract goals.

Some people think PIs can't do sth about the salaries but they hold so much power. They just don't advocate for us.