You work in a stock exchange, so you, more than anyone, are familiar with the concept of price discovery.
What something is worth = what someone is willing to pay for it
So, for ref, I also had 2 startups, I don’t have an MBA, and I don’t even have an engineering degree, but my TC is ~4X your dream CTC.
So instead of looking outwards for validation, look inwards. What are you good at? What did your startup experience give you that no one else has? Articulate it and then pitch it to whoever will listen.
Someone smart (like a founder) will recognize that you’ve been mispriced and take a chance. Until then, there’s very little chance of a company, in the absence of no salary disclosure laws, not benchmarking on your last paycheck.