In Monumenta Serica, Cambridge professor Sally K. Church addressed exactly this issue, in her article Zheng He: An Investigation into the Plausibility of 450-ft Treasure Ships

She exhaustively examines the historical record -- and is working from Chinese documents and primary sources, and concludes

[C]laims that Zheng He's ships were 450 ft long are, first, difficult to substantiate, and second, problematic. One reason why they are problematic is that they seem to defy the physical laws that govern the behaviour of all wooden sailing ships - Chinese, Western, or other - on the high seas. These laws may come to us via Western investigations, and one has to be careful about applying Western guidelines to Chinese conditions. However, in this case the guide- lines are at least in part the result of universal principles of marine science, engineering and naval architecture. Ships of the proposed size would have required extraordinary amounts of materials and complex infrastructural management but the historical records are strangely silent on this matter. Moreover, such enormous ships might not have been sound. Although we do not know how many of Zheng He's fleet were lost at sea, numerous eunuchs came and went on multiple voyages, as did Ma Huan and Fei Xin. Therefore Zheng He's ships must have been sound enough to transport them back home with a certain degree of reliability and predictability. All indications are that exaggeration has been at work in the accounts that mention the ships' enormous size, though we still are not absolutely sure of the exact mechanism by which it took place

[my bold]

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source:Church, Sally K. “ZHENG HE: AN INVESTIGATION INTO THE PLAUSIBILITY OF 450-FT TREASURE SHIPS.” Monumenta Serica, vol. 53, 2005, pp. 1–43. JSTOR, www.jstor.org/stable/40727457.

Professor Church also collaborated with naval architects to examine the technical aspects of such claims

A Naval Architectural Analysis of the Plausibility of 450-ft Treasure Ships