Personally, I think the “burn the ships” strategy is probably more viable for a serious endeavor, if you can afford (financially or otherwise) to do it. Save up 6-12 months of living expenses, make a plan, launch a barebones version, then make the jump and quit your job.

Speaking only personally here, but I think trying to just schedule in productive creative time doesn’t really work. There is no real enforced urgency and it’s too easy to think, “Well, I worked hard at my day job today, so I deserve to relax.” There is no “survival” mental state. But YMMV. I think it depends on whether you’re a “disciplined slow-but-steady worker” or if you thrive on being obsessed with what you’re working on.