I'm an atheist but when someone like him tells me that god gave him all of his equations - I'm not going to respond with "well ackshully". I'm going to ask them how we can make it easier for them to listen to god.
Assuming you don’t have a direct line to divinity yourself, you would need to have that profound genius in the first place to evaluate…
The original claim was that a genius should be able to easily and quickly attain mastery of any topic, given a grounding in the basics. Like, you give Mr. Super Genius IQ a book on quantum chemistry and the next day they’re putting things together so cleverly they are on the precipice of new discoveries.
Feynman actually did this a couple of times! But I think that just shows the “unreasonable usefulness” of mathematics, as well as his own spirit of curiosity. (And at least one time that we know of, he faked it by reading a colleague’s research before he presented it. Not to take credit, but just as a prank, so he could interrupt and predict every conclusion before the presenter finished.)
There aren't any Tony Starks who become experts in thermonuclear astrophysics overnight.
Richard Feynman was as close to this trope as you can get in reality, but insisted that his reputation for being able to solve difficult problems was due to having a "different box of tools" than others. And he obtained that by studying rather obsessively, well beyond assigned texts.
I have been lucky enough to know a few people who also might qualify as geniuses able to produce miraculous results. One of them decorated his laptop with the logos of defunct computer companies of the 1950s-1980s. He drew a lot of inspiration from papers and books that few others have read in thirty years.