The date 6/3 is not just the Dragon Boat Festival, it is also the 157th anniversary of the Jiangnan Shipyard. It's not just arbitrary.
However, I am not sure if the big boat will launch on that day.
The PLA Navy already had 7000-ton Type 052D with 2 QC280's. That class was limited by the two QC280's and could not go larger for major upgrade. And 7000 ton were not enough to accommodate more weapons and electronic systems. So apparently the PLA Navy needed a larger platform. But what could...