You're looking at this backwards - staying in a role that grinds you down isn't protecting your security, it's just delaying the crash. Burnout doesn't stay contained; it bleeds into everything else (sleep, relationships, your ability to think clearly about money) and makes you *more* vulnerable financially when it hits hard.
Here's what most people miss: start exploring options *while* employed, not after you've already quit. Spend a couple hours a week (seriously, just two) looking at other companies, roles, or even different industries that pay similar money but have better rhythms. You don't need to jump immediately - just knowing there's an exit route often takes the pressure off enough that you can think straight about what you actually need versus what you're just afraid to lose. Sometimes the shift happens just from that small action, and sometimes you find something better. Either way, you're not choosing between security and sanity; you're actually choosing between slow deterioration and active problem-solving.