I tested Ubuntu 18.04.3 on Intel Hades NUC this weekend.

Everything works fine except LG 5K display support.

I can't figure out a way to configure 5K resolution as there are 2 DP displays in system settings for the single LG 5K display.
Intel NUC use single thunderbolt 3 interface to transmit two DP signals to LG 5K display(believe this as this mechanism is officially confirmed from intel)

BTW 1, I must disable internal intel graphic card in BIOS, otherwise I can't boot into Ubuntu with only LG 5K display which has only thunderbolt 3 interface.
BTW 2, 5k is achievable in windows 10, no matter internal intel graphic card is enabled or not.

Thanks in advance.