I am not understanding why they have decided that Ryugu must have formed "beyond the snow line" when they also say that "the samples had formed within liquid water, at a temperature of about 81 to 117 degrees Fahrenheit."
We don't seem to think that Earth had to form "beyond the snow line" in order to have water, and "81 to 117 degrees F" sure sounds like a temperature that one can find on a planet with an atmosphere at about Earth's distance from the sun.
If they think that a planet with water cannot simply condense out of the gases and dust originally in the planetary nebula, why couldn't a rocky planet that condensed inside the snow line be provided by water like they think Earth was provided by water? If the planetary nebula was so chaotic and filled with colliding protoplanets, why couldn't bodies from beyond the snow line be flung into an orbit inside that line to make a protoplanet there become wet- which then gets destroyed by another collision to make Ryugu?