Probably somewhere in millions to tens of millions is upper limit of diminishing returns, unless you believe quack/unproven/illegal science and are willing to have children blood transfusions.
At $5M level you are pretty much all set, and at $10M and up - unless you are a consumption freak, you are really talking about generational wealth - i.e. money that will likely get passed down to your kids unless you try to find ridiculous ways to spend it.
This all assumes your goal in life isn't keeping up with the Jones's - if you fall into that trap, no amount of money will ever be enough.
I find it funny at times to think about if Larry Ellison is jealous of Zuckerberg's money, and Zuckerberg is jealous of Bezo's money, and Bezo's is jealous of Musk's money and Musk possibly being jealous of Bernard Arnault's.
If that is your personality - then you will never be happy.
Not sure what the rest of those points have to do with healthcare.