I LOVE the folks I work with and have a giant amount of freedom at work....
I wouldn't quit if I were you. Given your descriptions, it seems that your job provides a strong sense of purpose and identity, and is fairly interesting to boot.
You are free to quit if you want, of course. Your earnings and spending patterns have given you that right. But I don't hear a single thing that you want to do instead of working.
I quit work about a year ago and I love my life. I've learned to slow things down and relax. I have zero regrets and will never go back. But I have a very different story from you. I couldn't seem to convince myself that my job was important or meaningful. I couldn't see past the day to day slog and overall BS of it.
You appear to be in a very different situation, though. While you aren't literally curing cancer, you're in the ballpark, and you appear to be relatively satisfied - maybe even happy, ffs! -- with the work. And you make insane bank, too.
This is the dream life of most people, and you're living it. I suspect if you quit, after 2-3 months you'll be bored and have regrets. Many people have difficulty adapting to leisure and finding suitable replacement activities for the time work used to consume. Again, some people love it, and others just can't make the adjustment -- they need the stimulation, the structure, the system of rewards that work offers. Need to feel like they're giving back, part of a team, etc. I think there are elements of personality and individual programming in play here. We're not all wired the same way.
As others have said, if you really need a break, take a break. Find a spot at the end of a large project where it's all right for you to disappear for a month or two and figure out the details with the powers that be. People like you are, as a rule, great employees and most likely your employer would prefer to grant you some flexibility rather than losing you outright. It's not that weird to want some extended time off when you've been working for a couple of decades straight.
I just think that I am wasting limited time on earth as in Your Money or Your Life, at work.
It's not wasted! You appear to have one of the few jobs that is very clearly giving back to the world. There's nothing inherently bad about working -- don't let Your Money or Your Life (or hell, my own blog for that matter, where I rip on aspects of work constantly) make you think this way.
Only get to decide how you feel about your personal relationship with work. Nobody else -- You.
+1 to you are SWAMI. Own it. There's no shame in working hard and enjoying the hell out of it.