Good news, with updated stock kernel, I don't have any flickering.
$ uname -a Linux cerebro 5.15.0-40-generic #43-Ubuntu SMP Wed Jun 15 12:54:21 UTC 2022 x86_64 x86_64 x86_64 GNU/Linux
sudo lshw -c display *-display description: VGA compatible controller product: WhiskeyLake-U GT2 [UHD Graphics 620] vendor: Intel Corporation physical id: 2 bus info: pci@0000:00:02.0 logical name: /dev/fb0 version: 02 width: 64 bits clock: 33MHz capabilities: pciexpress msi pm vga_controller bus_master cap_list rom fb configuration: depth=32 driver=i915 latency=0 resolution=1366,768 resources: irq:136 memory:c0000000-c0ffffff memory:b0000000-bfffffff ioport:4000(size=64) memory:c0000-dffff
Good news, with updated stock kernel, I don't have any flickering.
$ uname -a
Linux cerebro 5.15.0-40-generic #43-Ubuntu SMP Wed Jun 15 12:54:21 UTC 2022 x86_64 x86_64 x86_64 GNU/Linux
sudo lshw -c display
capabilities: pciexpress msi pm vga_controller bus_master cap_list rom fb
configuration: depth=32 driver=i915 latency=0 resolution=1366,768 c0000000- c0ffffff memory: b0000000- bfffffff ioport: 4000(size= 64) memory:c0000-dffff
*-display
description: VGA compatible controller
product: WhiskeyLake-U GT2 [UHD Graphics 620]
vendor: Intel Corporation
physical id: 2
bus info: pci@0000:00:02.0
logical name: /dev/fb0
version: 02
width: 64 bits
clock: 33MHz
resources: irq:136 memory: