This was a worry for me when leaving my full time job in 2022 to work on open source. Our OSS project was able to pay rent, but was concerned about healthcare costs for my partner and me (NY state has extended COBRA coverage, but it's extremely expensive). My co-founder lives in Australia, which has free basic health care, so he was up for leaving his job before I was.

Taking the risk was one of the best decisions I've made, but if I had a chronic health condition/higher healthcare costs, probably would not have been comfortable.