"He wouldn't be able to make any notable contributions to mathematics for at least the next few years, or even longer."
Li Yilai's opinion might seem a bit extreme, but it represents the views held by the global mathematics community about Zhao Yi: that he is a computer genius whose proof of the Collatz Conjecture mostly relied on computer methods.
It is far more difficult to achieve in the field of mathematics than in computer science, because mathematics is a fundamental discipline, while computer science is a new field.
It is harder to make breakthroughs in fundamental disciplines.
Beyond that, the pure mathematics community both domestically and internationally is somewhat prejudiced against Zhao Yi's proof of the Collatz Conjecture. They mainly attribute this to his failure to use pure mathematical methods to prove it, instead of using binary diagrams, a tricky method. Also, Zhao Yi's youth has left some mathematicians feeling a bit awkward.