I looked through the documentation for this laptop. At its most technical, it simply lists the expansion port as supporting USB 3.1 Gen 1. Specifically, it makes no mention of whether any of the USB-C Alternate Modes are supported. Without either the DisplayPort or Thunderbolt Alternate Modes being supported, the maximum throughput of the port is limited to 10 Gb/s. My understanding is that, in order to display 4K@60Hz, you need to support a bit rate of approximately 18 Gb/s. Bottom line, unless one of the Alternate Modes is supported (and just wasn't mentioned in their online documentation), you only have the bandwidth to support 4K@30Hz.