It is certainly easy to question the veracity of the Ark narrative when we have no physical evidence left of such a structure, but we can’t legitimately discard the narrative on these grounds alone. After all, an absence of evidence is not evidence of absence.
What we need to do is to look back at ancient history and look for other prodigious structures to see what ancient people really were capable of.
For example, surely the Great Pyramid of Giza could be considered a structure of similar magnitude to the Ark. The biggest of the Giza pyramids originally measured over 145 meters tall and each side 230 meters long. Such a structure required over 2.3 million blocks of stone. Still to this day- when we have the technology to send people to the moon and genetically engineer organisms- nobody knows how these giant pyramids were constructed.
Ask yourself, would anyone seriously believe historical accounts of immensely giant pyramidal structures the size of the Great Pyramid if the structure didn’t still exist? Certainly not. Scholars would certainly claim that the stories were either entirely myth or highly exaggerated accounts of much smaller structures.
I’m sure most people would agree that the Great Pyramid of Giza is considerably more sophisticated and a substantially more of a monumental achievement than Noah’s wooden Ark.
When we look at some of the amazing structures that the ancient people of history were able to achieve- giant structures which still stand many thousands of years later- then suddenly the task that Noah had in building the Ark seems quite reasonable in comparison.