Well what i can say is that there's always the possibility that you find true happiness somewhere you don't expect. It's gotta be somewhere you don't expect cause otherwise we'd have it by now! And since you can't expect it, you can't forsee it. But it's there, waiting for its moment.
I came close a couple times but I held on and eventually found things. One thing that keeps me on is wanting to fix things. It can be difficult to witness the ugliness of the world in perfect detail through the internet, but i believe it's actually better than it ever has been, and it's only improved because people like me decided to make it that way. You're just past 50 and you've worked some incredibly important jobs, corporate culture feels dime a dozen these days but that doesn't mean anything about your actual self worth. I can't even imagine all the knowledge and experience you have now! Learning one thing isn't just one thing, it's learning about the world, learning how to learn, and about all the things connected to it. Your knowledge is much more general than the words on your resume.
I can't tell you how to fix money, i know that's an extremely difficult problem for a lot of people and I've seen it hurt. But i can say that you must be an incredibly capable and knowledgeable person, who has true potential. The kind of thing that doesn't happen in a job, but in a spark. The kind of spark that you don't even know exists until it does. I hope you're doing okay friend