I have read multiple biographies on Einstein. Very early on he showed his genius mind.
Please go and read and study this matter and have it resolved. The only place I read this theory was in leftist pronouncements.
Below is a small excerpt from Wiki on this matter.
In 1900, Einstein was awarded the Zurich Polytechnic teaching diploma, but Marić failed the examination with a poor grade in the mathematics component, theory of functions.[27]
There have been claims that Marić collaborated with Einstein on his celebrated 1905 papers,[28][29] but historians of physics who have studied the issue find no evidence that she made any substantive contributions.[30][31][32][33]
Einstein interacted in person with many of the great minds in Physics in the early 20th century. There was left in their minds no doubt about his incredible genius.
Someone of Einstein's amazing intellect does not happen but every 200-300 years.