What are the key upgrades in the Beelink SER6 Pro's I/O compared to the SER5?

The SER6 Pro adds HDMI 2.1 (two ports) and a USB-C port with DisplayPort Alt Mode for direct monitor output, giving three modern display outputs total. Networking is upgraded to 2.5 Gigabit Ethernet, and there are two USB 3.2 Gen 2 ports. It lacks a dedicated headphone jack but includes a 3.5mm audio combo jack.