Since the only 'upstream' USB interface on that display is its USB-C port, you'll need a USB-C to USB-A cable. The ability to use USB peripherals plugged into your display requires a USB data path to exist between the display and your system, which is not created by connecting a basic video cable. Try getting a Mini-DisplayPort to DisplayPort cable and you should be fine, since the specs for that system here clearly state that it supports displays up to 2560x1600. Your system does, but that capability as far as I'm aware has only ever supported up to 1080p, or I guess the very slightly higher 2048x1080 resolution, even when the DisplayPort source can support much higher resolutions when using native DisplayPort signaling. The only way to run both over a single cable would be with USB-C or Thunderbolt, but your system doesn't have USB-C and the U2719DC doesn't support Mini-DisplayPort to HDMI adapters rely on the Mini-DisplayPort source supporting 'Dual Mode DisplayPort', which allows it to send a native HDMI signal. One cable will be handling video, the other will be handling USB data.

This connection would be in addition to your video cable, not instead of. Some USB-C to USB-A cables only support USB 2.0. Make sure you get one that specifically supports USB 3.1 Gen 1. Mini-DisplayPort to HDMI adapters rely on the Mini-DisplayPort source supporting 'Dual Mode DisplayPort', which allows it to send a native HDMI signal.

Mac pro mid 2012 hdmi