How to run Ubuntu on new Dell XPS 15 7000 Series-7590

I have recently received a brand new Dell XPS 15 Series 7590 (2019) and installed the Ubuntu 18.04.2 LTS. While the system does start up and run, basically nothing works.

Most critically the CPU power management is broken. The power demand (and temperature) of the system is much higher than under Windows and after a couple of minutes the system decides that it needs to spin up the CPU to the temperature limit at 100 % idle, meaning that the system would quickly destroy the hardware. (Playing around with powertop, et. al. did not solve this.)

At the same time the system is unresponsive, even typing in terminals often leads to seconds long lags.

Other things that don’t work:

  • Touchpad (there is a Dell fix)
  • Changing screen brightness (OLED)
  • Too slow to watch Youtube
  • Very high CPU load when browser open
  • WiFi not recognized

So, how do I install Ubuntu on this laptop? Would Ubuntu 19 help? Or is this hardware just not supported?