I wonder if they started work on this before RAM prices spiked. Not sure how most people expect to be able to afford 128GB of RAM in today's market. Also, one USB-C and one USB-A is pretty minimal connectivity for an otherwise high-powered, wildly-expensive laptop.
It's probably a Lenovo board, which usually has most of the IO on a daughter board connected to the Mainboard. Only the USB-C that had the display port/HDMI alt mode sits on the Mainboard.
That's a widespread practice among OEMa that want to use the same board in a 13/14" chassis and a 15/16" chassis. They just need a longer cable to the daughterboard for the larger laptop. That usually means all the high-power and high-speed ports are on the same side of the laptop and on the far side you get USB 3.0 and headphone ports.