I have one of those LG 4k UltraFine monitors for work at home that are just “made for Apple” by supporting only Thunderbolt. That works perfectly as long as you use an Apple product, but falls short if you want to use the same monitor also for your gaming pc which usually just have HDMI or DP graphical output.
In the ideal world I just wanted to unplug the TB cable once I’m finished with work and plug it into the gaming rig, so I could keep using the mouse & keyboard without having to mess around. Turns out this was a bit more difficult than expected and took roughly a 1 year to finish due to a horrible motherboard choice. You find the full build at the bottom 👇.
To get around the HDMI/DP issue, you will need to find a motherboard that has a DP in and a Thunderbolt output. That allows you to loopback the graphic output to Thunderbolt by connecting a cable from your graphic cards output to the DP in. Definitely find a very short cable for this.