One update: somebody on the Ask Ubuntu Stack Exchange suggested the possibility that this could all be related to the update from the 5.15 kernel to the 5.19 kernel (which, relatedly or coincidentally, happened at almost exactly the same time as the Dell-specific updates mentioned above. Anybody else having issues with that kernel upgrade?

It seems many others are having exactly the same problem with the same timing on the same machine with the same OS:
https://www.dell.com/community/Inspiron/Horizontal-lines-appearing-on-my-display-Ubuntu/m-p/8353821#M159112
https://askubuntu.com/questions/1455653/horizontal-colored-lines-appearing-on-display-ubuntu-22-04
https://askubuntu.com/questions/1455925/dell-xps-13-plus-9320-horizontal-lines-static-after-installing-latest-release

I'm having the same problem with my Dell XPS 13 Plus. I noticed the monitor with a slightly yellowish white and when I move the mouse over some elements, horizontal bands of colored pixels appear. My bios version is older than the current version.

I have already changed the kernel and even versions of Linux. I put Arch Linux, but first I created a recovery USB so I could go back to Ubuntu again. In both Arch and Ubuntu, in different versions of the linux kernel the problem remained.

@prdm0 So, I'm not sure. On my machine the problem was definitely introduced by the update from the 5.15 kernel to the 5.19 kernel (pushed to Ubuntu 22.04 LTS users a little over a week ago), but it presumably got introduced in some version between 5.15 and 5.19, possibly a while ago, and that version might have been pushed to different distros at different times. I would try specifically downgrading to 5.15 to see if that helps and/or add the i915.enable_psr=0 flag to the GRUB_CMDLINE_LINUX_DEFAULT string in your /etc/default/grub file. All details are here. If those don't have any impact, you might be facing a different problem.

I was able to fix the issue of the colored horizontal pixels. I just think the monitor could deliver more. I noticed it a little dark and with very slightly yellowish white tones.

For me, the image below is slightly yellowish. The background white should be better.

It also appears to me that the monitor is not properly calibrated for colors and brightness. For example, the white in the image below is not in the proper white light.

Maybe with some color calibration software it will work.

@tcquinn  , Dell informed in the ticket what would be the disadvantage of making i915.enable_psr=0 flag to the GRUB_CMDLINE_LINUX_DEFAULT? I suppose that if they opened a case with Canonical to solve the problem, then there is some loss in using this solution, for example, not using all the quality that could be delivered by the screen.

@prdm0 I don't know. I think the feature that is being disabled is PSR2 selective fetch. If you Google that phrase, you'll find all kinds of threads about problems relating to this feature. Most of the solutions seem to involve disabling it (as Dell suggested).

Just for the record, on Pop OS, just do:

sudo echo "options i915 enable_psr=0" >> /etc/modprobe.d/i915.conf

sudo update-initramfs -c -k $(uname -r)

reboot

I'm using Pop OS.

I had tried switching back to Arch and Manjaro, but it's still not legal to use Dell XPS 9320 on Arch or Arch-based systems.