Startups even in successful cases are just break even working at AFGAM. Usually you'll quickly be throwing away $100k/yr in income instead. And that $60k/yr your not putting in your stock brokerage account you could of used for whatever bootstrapped digital business or financial independence base you could of done instead. Over 8 years the difference can mean a literal million dollars in the bank.
Working at AFGAM won't make you lose your soul, and you'll learn a lot of stuff that you wouldn't learn in a startup. If you work at both types, you'll quickly realize that working at a SV startup and working at Twitter or FB is not that much different.
A lot of startups have fun, but writing bad disposable code is the standard operating procedure. Mentorship is usually non-existent. Wanting to write something quality is usually difficult to get approved because you might die tomorrow. Long hours are very typical.
I would also suggesting looking at this article: https://deardesignstudent.com/8-reasons-to-turn-down-that-st... , #4 is especially relevant.