What about good old philosophy?
Philosophy already has a long tradition of birthing new sciences, a long tradition of encouraging polymath thinking and a long tradition of estabilishing foundational ways of thinking.
At my present workplace, I've noticed that the people who have polymath tendencies tend to have physical science degrees.
EDIT: Most noticeably from the absolute garbage code I had to make work that these 'genius coders' produced. They were good at physics, but they should never have written any code if it could have been prevented.
EDIT#2: And an adjacent poster "FredPret" demonstrated it perfectly. Let's derive Evolution from particle physics... and go! (Sean Carroll is a good antidote to this attitude... he knows there are levels of description that are useful.)
It's interesting the converse is true: techbros often think they would've excelled in physics PhD programs
(Self-referentially: Even for me... So take what I said above with a grain of salt, but I'm pretty sure this has solid research behind it.)
Garbage code isn't exclusive to physicists. The coders often complain when they have to deal with code from other coders.
And physicists gonna code. The last nontrivial problem to be solved without computation was probably solved sometime in the 1930s. And the most powerful "physics software" is a coding stack.
In my own case I've made a career long effort to learn good coding practices, but I don't expect my code to go straight into production.
As for deriving evolution from particle physics, I don't think I've known a physicist who would recommend that.
The thing is, the limitations of our tools don't excuse us from having to do research and make things work. Or from finding employment. ;-) So we tend to be opportunists in terms of synthesizing knowledge from multiple fields.
Somehow, this was extended to computers too. The three of them are now cross-pollinating. It happens with other sciences too, but it seems it started earlier in physics and math.
In that sense, anyone with knowledge consisting of "a little bit of computer science plus one single other trade" likely represents the new baseline, not polymathy (similar to the previuous one "a little bit of math plus one single other trade").
So, if you want to be a CS polymath, you'd have to know what CS will look like when all this cross pollination settles down. I think it will look very different from what it is now, it is such a new science. Impactful, but very new.
Even biology had this cross-pollination thing. Lots of fields took evolution ideas, some in very dangerous ways. This influence survives to this day (neural networks, evolutionary algorithms, etc), but it is more like a cargo cult than real intersection. It resembles more biology from the past than what biologists think today.
Polymaths right now are probably working in the fields with less computers, trying to fill that gap. In the cross-pollination analogy, they're the first to waggle dance.
In that sense, I see a history+biology polymath more rare and special than a cs+math polymath, for example. They probably have a more unique and singular perspective on science than the more estabilished swarm of existing cs+math polymaths.
As I mentioned in another post. physics ran out of problems that were solvable by hand with equations roughly a century ago. Feynman managed rooms full of "computers" who were people operating mechanical calculating machines for nuclear physics problems. When digital computers gradually became available, physicists were already waiting in line to use them. Von Neumann promoted government funding of academic computing facilities with an eye towards using the computers for bomb yield calculations.
The software industry gradually began to emerge roughly a decade later.
Ironically, I was "a little math plus some other trade." I learned programming in high school (1981) but had a summer internship at a computing facility and it didn't spark my interest in programming as an occupation, so I majored in math. My other intended trade -- being a rock star -- never materialized, and I ended up with a second major in physics instead. But I've always been an avid programmer, and I do most of my computational and experimental work by coding. All of my fellow physics grad students were coders, and many went into programming when their luck ran out in the grim physics job market.
Historically, yes, but what about in recent years? I know there have been some new fields that arose out of philosophy, but this seems to have slowed down.