It depends on how you measure the volume of the rainfall. Taipei is 105 square miles, whereas Houston is 667 square miles. Lynn dumped 66.93 inches of rainfall in one particular spot in Taipei, and Harvey dumped 40 inches over most of Houston, with a peak measurement of 51.88 inches in nearby Cedar Bayou. This implies a larger total volume was deposited on Houston by Harvey than was deposited on Taipei by Lynn, but this may mostly be because of Houston’s larger geographical footprint.
Technically, Ethan’s statement is likely correct. What’s unknown is whether Harvey dumped more total water or more water per hour over the course of its life than any other cyclone in history. My guess is one of the Pacific super typhoons or Cape Verde hurricanes holds the record for most total, based largely on lifespan and storm diameter. Harvey, for instance, lasted 16 days. Ivan, in 2004, lasted 22 days. In terms of volume of water per hour, I have no idea.