Comment 25 for bug 1958620

found some other reports that claim i915.fastboot=0 is a workaround, and can confirm it does work around the issue on jammy's current 5.15 kernel.

https://www.reddit.com/r/pop_os/comments/scqr4n/dell_xps_15_9575_screen_flickering_upon_boot/
https://bugs.archlinux.org/task/72134
https://gitlab.freedesktop.org/drm/intel/-/issues/4952