Your fifth startup will be successful. First four will not. So, save money on first four startups for the fifth one, e.g. commit 10k for a first startup and try

Your fifth startup will be successful. First four will not. So, save money on first four startups for the fifth one, e.g. commit 10k for a first startup and try to make it profitable first (you will fail with probability of 99.9%), then commit 20k for a second one, and so on. Don't leave your job until a fourth startup at least.