Ubuntu / PopOS 21.04 - Screen blinking
Just had this problem on the exact same processor. It turned out that an Intel power-optimization feature has to be turned off via grub.
Add "i915.enable_psr=0" to the default GRUB command line in /etc/defaults/grub, so it reads:
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash i915.enable_psr=0"
The flickering is gone after activating this GRUB.
$ sudo update-grub