I did this, quit my job and ran my startup idea full-time, without enough funding, and I have a family and a mortgage. I loved it, and I regret it, and I don't regret it, all at the same time. I had some savings, but I've used it all. I've been going full-time for a lot longer than I thought I could, but I have to get a job again. My startup is making money but not enough to pay the founders, and it will be a while before we can go full-time again. I underestimated how long bootstrapping takes, and I've since watched other people underestimate how long bootstrapping takes.
It has been more fulfilling to go full time. I'm doing exactly what I want, and I'm responsible for my own success or failure. I have learned more than I would have by doing the side project on the side. We did run our project on the side for a couple years, and it was really frustrating. Going full time was a huge breath of fresh air, and a lot more fun than adding 20-40 hours a week on top of a 40+ hour full time job. I've also have a lot more time for my family, it just came at the cost of not having a lot of money for my family.
My main takeaway from having tried this is next time I'm going to do more preparation and have a runway in place before I quit and go full-time. Whether it's savings or VC funding or whatever, not having control over the end of the runway has been a mistake.