Indeed, I’ve just hacked-in kernel 6.8 on my existing Kubuntu 22.04.4 LTS installation and now it’s able to resume from the sleep.
So we can be pretty sure that the issue is due to outdated kernel version.
Update 1:
Still, there is one regression. Once in a while laptop fails to wake from sleep, but in a different way.
I am pressing the keyboard, pressing the power button and nothing happens, as if the keyboard module is completely powered off or detached from the mainboard. Power button just keeps blinking its LED.
Please note that I am using s2Idle sleep, not a deep sleep.
Update 2:
For now, solved the resume issue by installing the 6.5.0-1025-oem kernel.