Well that is what sources are for.
This shows, on page 44, that technologically that the ships as described are unlikely to have existed. Wooden ships of that size are possible they just didn't have access to the proper types of wood and they built the hull the wrong way to make it feasible. That entire article however does not in anyway dispute that the voyages happened. Like I said they happened they were probably just embellished in the sense that the fleet wasn't the size it is described as so that calls into doubt how big it must have truly been. Doesn't mean it didn't happen and you could still have the whole adventure happen with just one of those ships honestly.
And if you are entirely curious on page 47 they discuss the different types of ships and their possible uses. This is using modern shipbuilding combined with historical accounts just to look at whether or not they could do what they were supposed to. Basically they weren't great ocean going vessels and kinda lacked space but their historical roles are most likely accurate.