I have an XPS-15 7590 running 18.04 and I have both the Intel & NVIDIA graphics card. The specs are basically: i9 processor, NVIDIA GTX 1650 GPU, and 4K OLED. I've been trying to work on the NVIDIA & Intel drivers (installed Nvidia proprietary and iwlwifi Intel driver) through the Software & Updates manager and tried to install simulators like CARLA, Lgsvl and so on. I tried to switch to the NVIDIA graphics card with this command (because Nvidia X server settings didn't work):
sudo prime-select nvidia
After a reboot, I am welcomed with a screen overlaid by repeating artifacts:
I tried running the same command sudo prime-select intel
but the situation persists. Now when I look at Nvidia X Server settings manager (it decided to work again for some reason), Intel is selected so I'm definitely not on the Nvidia GPU.
This isn't the only screen issue I'm having. Apps like Android Messages shows vertical screen ripping as you can see below.
Although I don't mind doing a fresh install, I don't think that is necessary as I believe there are existing solutions to this problem. Not only that but a fresh install is pretty much pointless since this problem will start once again when I install my necessary software.
FOLLOW-UP:
A clean reinstall of 18.04 solved the problem.